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Horn L, Windhager S, Juricka N, Bugnyar T, Massen JJM, Markova G. Investigating the effects of prenatal testosterone exposure (via 2D:4D) and socio-relational factors on 3-6-year-old preschoolers' prosocial choices. Early Hum Dev 2024; 195:106055. [PMID: 38875940 DOI: 10.1016/j.earlhumdev.2024.106055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/25/2024] [Accepted: 05/30/2024] [Indexed: 06/16/2024]
Abstract
BACKGROUND AND AIMS Prosocial behavior such as helping and sharing develops early in childhood. Yet very few studies have investigated physiological and relational factors shaping prosociality among children. Here, we systematically examined the role of prenatal androgen exposure alongside prestige, dominance, and friendship in 3-6-year-old preschoolers' prosocial sharing with familiar peers. METHODS We tested a sample of 65 children, predominately of European descent. We used a cost-free direct-interaction prosocial choice task to assess children's prosocial tendencies. Second-to-fourth digit ratio (2D:4D) was used as a retrospective biomarker for prenatal androgen exposure. Prestige was measured through behavioral observations of interaction partners and visual regard, dominance through teacher questionnaires, and friendship via peer preference assessments. RESULTS We found that children acted prosocially when tested with a familiar peer. Children with lower 2D:4D (higher prenatal androgen exposure) behaved more prosocially. Further, there were marginal associations between the donors' prosocial tendencies and their visual regard as a proxy of their prestige (positive effect) and their teacher-rated dominance relative to the recipient (negative effect). Neither age, sex, nor friendship influenced prosocial choices. CONCLUSIONS Prenatal androgen exposure, approximated via 2D:4D, was associated with prosocial behavior. In contrast to previous research in older children, higher exposure was related to stronger prosocial tendencies, which corresponds to earlier findings on fairness in adults. Our findings point towards a potential role of sex steroids in the early development of children's social behavior, but they have to be interpreted with caution due to the small sample size of the current study. Nevertheless, they underscore the importance of integrating biological and psychological perspectives, while also highlighting the significance of studying the development of prosocial behavior within peer groups.
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Affiliation(s)
- Lisa Horn
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria.
| | - Sonja Windhager
- Department of Evolutionary Anthropology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria; Human Evolution and Archaeological Sciences (HEAS), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria.
| | - Nina Juricka
- Department of Developmental and Educational Psychology, University of Vienna, Liebiggasse 5, 1010 Vienna, Austria
| | - Thomas Bugnyar
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria.
| | - Jorg J M Massen
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria.
| | - Gabriela Markova
- Department of Developmental and Educational Psychology, University of Vienna, Liebiggasse 5, 1010 Vienna, Austria.
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Ernsten L, Körner LM, Heil M, Schaal NK. The association between 2D:4D digit ratio and sex-typed play in children with and without siblings. Sci Rep 2024; 14:15231. [PMID: 38956189 PMCID: PMC11219774 DOI: 10.1038/s41598-024-65739-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 06/24/2024] [Indexed: 07/04/2024] Open
Abstract
The 2D:4D digit ratio is commonly used as a surrogate possibly reflecting prenatal testosterone levels. Indirect evidence comes from studies investigating the association between 2D:4D and human characteristics that likely relate to prenatal testosterone. In children, sex-typed play reveals large sex differences early in development and an influence of prenatal testosterone is likely. Findings on the association between 2D:4D and children's sex-typed play are heterogeneous and other influences on the development of sex-typed play have been suggested, most of all social influences like siblings, their sex and birth order. The current study examined the association between right and left 2D:4D, a proposed surrogate for prenatal testosterone exposure, which was assessed in right and left hands of N = 505 6-month-old children, and sex-typed play behavior, which was evaluated 3.5 years later using the Pre-School Activities Inventory (PSAI), and the influence of siblings. To capture differential effects of siblings' sex and birth order, dummy-coded variables were used reflecting having no siblings as well as older or younger sisters or brothers. Multiple regression models were used to investigate the association between PSAI scores and sex, right and left 2D:4D, being a singleton as well as having an older or younger sister or brother. It was shown that sex and having an older brother were significant predictors for sex-typed play. Effects were further disentangled by conducting separate regression analyses in boys and girls. In boys, a significant association between PSAI scores and having an older brother was revealed, in girls, no significant associations were found. Results are discussed highlighting the non-significant association between 2D:4D and children's sex-typed play, which weakens the applicability of 2D:4D as a surrogate reflecting influences of prenatal T. Further, the importance of social factors like siblings on children's sex-typed play is discussed.
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Affiliation(s)
- Luisa Ernsten
- Faculty of Mathematics and Natural Sciences, Institute of Experimental Psychology, Heinrich Heine University, Düsseldorf, Germany.
| | - Lisa M Körner
- Faculty of Mathematics and Natural Sciences, Institute of Experimental Psychology, Heinrich Heine University, Düsseldorf, Germany
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Martin Heil
- Faculty of Mathematics and Natural Sciences, Institute of Experimental Psychology, Heinrich Heine University, Düsseldorf, Germany
| | - Nora K Schaal
- Faculty of Mathematics and Natural Sciences, Institute of Experimental Psychology, Heinrich Heine University, Düsseldorf, Germany
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Aslan Genç H, Özcan Morey A. Lower digit length ratio and aggression in adolescents and young adults with boxer's fracture: A case-control study. Aggress Behav 2023; 49:679-686. [PMID: 37467363 DOI: 10.1002/ab.22106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/09/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023]
Abstract
Recent evidence shows that a lower second-to-fourth digit ratio (2D:4D), which is a sexually dimorphic trait and the indicator of prenatal testosterone exposure, may be associated with aggressive behaviors. In this cross-sectional, case-control study, we investigated: (1) Are the aggression and impulsivity levels and emotional problems higher? (2) Is the 2D:4D ratio lower in adolescents and young adults who presented with a fifth metacarpal neck fracture (boxer's fracture) compared to controls? (3) Is the digit ratio correlated with aggressive measures in individuals with a fifth metacarpal neck fracture? Seventy-one consecutive patients presented with a fifth metacarpal neck fracture within the age range of 11-25 years old comprised the study group. The control group consisted of 71 age and sex-matched subjects without a history of aggression-related injury. The aggression, impulsiveness, and psychosocial well-being were measured by self-reported questionnaires. 2D:4D was measured by conventional radiography. The 2D:4D ratio was similar between groups, however, when the analyses were conducted separately for sex, females in the study group showed lower 2D:4D than females in the control group (p = 0.001). The aggression level of the study group, measured by the Buss-Perry Aggression Questionnaire was higher than the control group (p = 0.014). The impulsiveness scores on the Barratt Impulsiveness Scale-11 were similar (p = 0.60) and the total difficulty score on the Strengths and Difficulties Questionnaire was higher in the study group (p = 0.009). A lower 2D:4D ratio significantly predicted verbal and total aggression scores (p = 0.036, p = 0.032, respectively). Our findings suggest that females with a history of aggression-related injury have lower 2D:4D, and a lower 2D:4D is correlated with higher aggression levels in both sexes. Understanding and addressing aggression in these patients may help prevent further self-inflicted injuries.
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Affiliation(s)
- Herdem Aslan Genç
- Department of Psychiatry, Koç University School of Medicine, Istanbul, Turkey
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Siegmann EM, Eichler A, Buchholz VN, Gerlach J, Pontones CA, Titzmann A, Arnaud N, Consortium IMACM, Mühle C, Beckmann MW, Fasching PA, Kratz O, Moll GH, Kornhuber J, Lenz B. Effects of an App-Based Mindfulness Intervention during Pregnancy on the Infant's Prenatal Androgen Exposure: A Randomized Controlled Pilot Trial. J Clin Med 2023; 12:6142. [PMID: 37834786 PMCID: PMC10573842 DOI: 10.3390/jcm12196142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/18/2023] [Accepted: 09/20/2023] [Indexed: 10/15/2023] Open
Abstract
Prenatal androgen exposure modulates the development of the brain, with lasting effects on its function and behavior over the infant's life span. Environmental factors during pregnancy, in particular maternal stress, have been shown to influence the androgen load of the unborn child. We here addressed the research gap on whether a mindfulness intervention or a pregnancy education administered to pregnant women more affects the androgen exposure of the unborn child (quantified by the proxies of second-to-fourth digit length ratio (2D:4D) and anogenital distance assessed one year after delivery and at delivery, respectively). Moreover, we tested the mindfulness intervention's effects on maternal perceived stress, anxiety, depressiveness, and mindfulness. Pregnant women (gestation weeks 8-14) were randomized to a 15-week app-based mindfulness-oriented intervention (N = 72) or a pregnancy education intervention (control condition; N = 74). The mindfulness-oriented group did not significantly differ from the pregnancy education group in infants' 2D:4D or anogenital distance (partial η2 ≤ 0.01) or in maternal stress, anxiety, depressiveness, or mindfulness. However, the descriptive results indicate that across pregnancy, stress and anxiety decreased and mindfulness increased in both groups. Overall, this study did not show that the mindfulness intervention (relative to the pregnancy education) reduced the prenatal androgen exposure of the unborn children or improved the maternal outcomes significantly.
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Affiliation(s)
- Eva-Maria Siegmann
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Anna Eichler
- Department of Child and Adolescent Mental Health, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Verena Nadine Buchholz
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Jennifer Gerlach
- Department of Child and Adolescent Mental Health, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Constanza A. Pontones
- Department of Obstetrics and Gynecology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Adriana Titzmann
- Department of Obstetrics and Gynecology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Nicolas Arnaud
- German Centre for Addiction Research in Childhood and Adolescence, University Medical Centre Hamburg–Eppendorf, 20246 Hamburg, Germany
| | | | - Christiane Mühle
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Matthias W. Beckmann
- Department of Obstetrics and Gynecology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Peter A. Fasching
- Department of Obstetrics and Gynecology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Oliver Kratz
- Department of Child and Adolescent Mental Health, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Gunther H. Moll
- Department of Child and Adolescent Mental Health, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Bernd Lenz
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany
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Ernsten L, Körner LM, Schaper ML, Lawrenz J, Richards G, Heil M, Schaal NK. The association of prenatal amniotic sex hormones and digit ratio (2D:4D) in children aged 5 to 70 months: A longitudinal study. PLoS One 2023; 18:e0282253. [PMID: 36952430 PMCID: PMC10035896 DOI: 10.1371/journal.pone.0282253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 02/07/2023] [Indexed: 03/25/2023] Open
Abstract
The sex difference of the 2D:4D digit ratio (female > male)-a proposed marker for prenatal testosterone exposure-is well established. Studies suggest it already exists in utero and is of moderate effect size in adulthood. However, evidence for the claim that 2D:4D reflects prenatal androgen action is limited, and the sex difference may exhibit lability during childhood. In the present study, 244 mothers were recruited in the course of an amniocentesis examination (performed between gestational weeks 14 and 18). Prenatal testosterone (T) and estradiol (E) levels were determined from amniotic fluid for boys and girls. The majority (97.4%, n = 114) of available female T levels (n = 117) were found below the level of quantification. Therefore, only male amniotic fluid data (n = 117) could be included for the analysis of associations between amniotic sex hormones (T levels and T to E ratio (T/E)) and 2D:4D. The families were then invited to each of the five consecutive follow-ups (ages: 5, 9, 20, 40, and 70 months) where children's 2D:4D was measured for both hands. The alternative marker D[r-l] reflects the directional asymmetry of 2D:4D (right subtracted by left 2D:4D) and was subsequently calculated as an additional measure for prenatal T exposure. No significant correlations between amniotic T or the T/E ratio (measured between week 14 and 18 of gestation) with 2D:4D respectively D[r-l] were observed for any time point. There was a significant sex difference (females > males) and a significant age effect with moderate correlations of 2D:4D between time points. 2D:4D increased between 20 and 40 months and between 40 and 70 months of age. The findings raise questions regarding the applicability of 2D:4D as a marker for prenatal androgen action and are discussed in terms of the reliability of obtained digit ratio data as well as in terms of the developmental timing of amniocentesis.
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Affiliation(s)
- Luisa Ernsten
- Department of Experimental Psychology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Lisa M Körner
- Department of Experimental Psychology, Heinrich-Heine-University, Düsseldorf, Germany
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Marie Luisa Schaper
- Department of Experimental Psychology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Judith Lawrenz
- Department of Experimental Psychology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Gareth Richards
- School of Psychology, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Martin Heil
- Department of Experimental Psychology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Nora K Schaal
- Department of Experimental Psychology, Heinrich-Heine-University, Düsseldorf, Germany
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6
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Levin RN, Erickson-Schroth L, Mak K, Edmiston EK. Biological studies of transgender identity: A critical review. JOURNAL OF GAY & LESBIAN MENTAL HEALTH 2022. [DOI: 10.1080/19359705.2022.2127042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Rachel N. Levin
- Departments of Biology and Neuroscience, Pomona College, Claremont, CA, USA
| | | | - Kristie Mak
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - E. Kale Edmiston
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Tasos E. To What Extent are Prenatal Androgens Involved in the Development of Male Homosexuality in Humans? JOURNAL OF HOMOSEXUALITY 2022; 69:1928-1963. [PMID: 34080960 DOI: 10.1080/00918369.2021.1933792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Endocrine variations, including possibly reduced exposure to androgens, may contribute to the development of male homosexuality, with animal models demonstrating same-sex mate preference with altered exposure during prenatal or early postnatal development. As similar studies in humans are impossible, indirect physical and cognitive measures of androgen exposure are used. Some studies suggest that physical measures affected by prenatal androgens, including the index-to-ring finger ratio, growth indices, and facial structure, are more "feminine" in gay men. Gay men also exhibit significant childhood gender non-conformity and a "feminized" anatomical and functional brain pattern in sexual arousal, as well as domains such as language, visuospatial skills and hemispheric relationships. However, many of these results are equivocal and may be confounded by other factors. Research has also been hampered by inconsistencies in the reporting of sexual orientation and the potentially unrepresentative populations of gay men studied, while additional complexities pertaining to gender conformity and sexual role may also influence results.
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Affiliation(s)
- Emmanouil Tasos
- School of Clinical Medicine, University of Cambridge, Cambridge, UK
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8
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Jägetoft Z, Unenge Hallerbäck M, Julin M, Bornehag CG, Wikström S. Anthropometric measures do not explain the 2D:4D ratio sexual dimorphism in 7-year-old children. Am J Hum Biol 2022; 34:e23776. [PMID: 35751545 PMCID: PMC9540332 DOI: 10.1002/ajhb.23776] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 12/05/2022] Open
Abstract
Objectives Digit ratio (2D:4D) might reflect prenatal testosterone exposure and has been used as a putative marker for androgen related outcomes. However, such associations might be inflicted by confounders. Application of 2D:4D in epidemiological research motivate identification of biological background determinants. We examined sex, anthropometric measures, and maternal factors as determinants of 2D:4D in Swedish 7‐year‐old children. Methods The study was embedded in the Swedish Environmental, Longitudinal, Mother and Child, Asthma and Allergy (SELMA) pregnancy cohort. A total of 870 pre‐pubertal children, median 7.5 years of age, were studied. A single assessor performed digit measurements from scanned photocopies using computer software. Child anthropometric measurements investigated were hand size, birthweight, recumbent birth length, standing height, weight, BMI, body fat percentage, and waist/hip circumference. Maternal factors included age, pregnancy length, parity, and education. Results We found a significant sexual dimorphism regarding digit lengths and 2D:4D, boys on average presenting a lower 2D:4D than girls also after adjustment for summed finger lengths and body fatness. In crude analyses, maternal age correlated with 2D:4D across the whole population and in females but not in adjusted models. No other study variables were associated with 2D:4D. Conclusion Digit ratio showed sexual dimorphism at the age of seven and seems to represent a true sex difference rather than an artifact and bias from hand size, body size or body fat content. Among the rest of our investigated variables, we found no determinants constituting important confounders in future research on 2D:4D ratio.
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Affiliation(s)
- Zebulohn Jägetoft
- Centre for Research and Education, County Council of Värmland, Karlstad, Sweden
| | - Maria Unenge Hallerbäck
- Centre for Research and Education, County Council of Värmland, Karlstad, Sweden.,Department of Health Sciences, Karlstad University, Karlstad, Sweden.,School of Medical Science, Örebro University, Örebro, Sweden
| | - Maria Julin
- Västerås Hospital, County Council of Västmanland, Västerås, Sweden
| | - Carl-Gustaf Bornehag
- Department of Health Sciences, Karlstad University, Karlstad, Sweden.,Department of Preventive Medicine, Ichan School of Medicine at Mount Sinai, New York, New York, USA
| | - Sverre Wikström
- Centre for Research and Education, County Council of Värmland, Karlstad, Sweden.,Department of Health Sciences, Karlstad University, Karlstad, Sweden.,School of Medical Science, Örebro University, Örebro, Sweden
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Ernsten L, Körner LM, Heil M, Richards G, Schaal NK. Investigating the reliability and sex differences of digit lengths, ratios, and hand measures in infants. Sci Rep 2021; 11:10998. [PMID: 34040007 PMCID: PMC8155043 DOI: 10.1038/s41598-021-89590-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/23/2021] [Indexed: 11/08/2022] Open
Abstract
Hands and digits tend to be sexually dimorphic and may reflect prenatal androgen exposure. In the past years, the literature introduced several hand and digit measures, but there is a lack of studies in prepubertal cohorts. The available literature reports more heterogeneous findings in prepubertal compared to postpubertal cohorts. The comparability of the available studies is further limited by the study design and different measurement techniques. The present study compared the reliability and sex differences of available hand and digit measures, namely digit lengths of 2D, 3D, 4D, 5D, digit ratios 2D:4D, 2D:5D, 3D:4D, 3D:5D, 4D:5D, relative digit lengths rel2, rel3, rel4, rel5, directional asymmetry of right and left 2D:4D (Dr-l), hand width, length, and index of 399 male and 364 female 6-month-old German infants within one study using only indirect and computer-assisted measurements. The inter-examiner reliability was excellent while the test-retest reliability of hand scans was only moderate to high. Boys exhibited longer digits as well as wider and longer hands than girls, but smaller digit ratios, with ratios comprising the fifth digit revealing the largest effect sizes. Other hand and digit ratios revealed sex differences to some extent. The findings promote the assumption of sexual dimorphic hand and digit measures. However, by comparing the results of the available literature, there remains an uncertainty regarding the underlying hypothesis. Specifically in prepubertal cohorts, i.e. before the influence of fluctuating hormones, significant effects should be expected. It seems like other factors than the influence of prenatal androgens contribute to the sexual dimorphism in hand and digit lengths.
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Affiliation(s)
- Luisa Ernsten
- Department of Experimental Psychology, Heinrich-Heine-University, Universitätsstraße 1, 40225, Düsseldorf, Germany.
| | - Lisa M Körner
- Department of Experimental Psychology, Heinrich-Heine-University, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Martin Heil
- Department of Experimental Psychology, Heinrich-Heine-University, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Gareth Richards
- School of Psychology, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Nora K Schaal
- Department of Experimental Psychology, Heinrich-Heine-University, Universitätsstraße 1, 40225, Düsseldorf, Germany
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10
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Rodríguez-Ramos Á, Moriana JA, García-Torres F, Ruiz-Rubio M. Emotional stability is related to 2D:4D and social desirability in women: Possible implications on subjective well-being and psychopathology. PLoS One 2021; 16:e0248368. [PMID: 33690629 PMCID: PMC7942991 DOI: 10.1371/journal.pone.0248368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 02/23/2021] [Indexed: 01/07/2023] Open
Abstract
Emotional stability-Neuroticism is a complex construct influenced by genetics and environmental factors. Women tend to exhibit higher neuroticism scores than men, which may be associated with an increased risk of suffering from some common mental conditions. Some authors have pointed out the influence of sex hormones, since they induce sexual differentiation of the brain that can lead to sex-specific behaviors. 2D:4D digit ratio is commonly used as a marker of prenatal sex hormones. In this study we analyzed whether there was an association between 2D:4D and personality measured through the BFQ in a homogeneous sample of 101 young women college students. We found a positive association between 2D:4D and emotional stability, as well as with its subdimensions emotion control and impulse control. This association could be quadratic and nonlinear. However, no association was found with the other four dimensions. We also measured anxiety, depression and global life satisfaction, variables related to neuroticism. We observed that emotional stability is positively associated to social desirability and global life satisfaction, and negatively related to anxiety and depression. On the other hand, we did not find any association between 2D:4D and anxiety, depression, and global life satisfaction. These results can be linked to other aspects such as subjective well-being and psychopathological symptoms. This study may help to better understand how these constructs are related and could lead to future projects to elucidated how these variables influence personality.
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Affiliation(s)
- Ángel Rodríguez-Ramos
- Department of Genetics, University of Córdoba, Córdoba, Spain
- Department of Psychology, University of Córdoba, Córdoba, Spain
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), Córdoba, Spain
- University Hospital Reina Sofía of Córdoba, Córdoba, Spain
| | - Juan Antonio Moriana
- Department of Psychology, University of Córdoba, Córdoba, Spain
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), Córdoba, Spain
- University Hospital Reina Sofía of Córdoba, Córdoba, Spain
| | - Francisco García-Torres
- Department of Psychology, University of Córdoba, Córdoba, Spain
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), Córdoba, Spain
- University Hospital Reina Sofía of Córdoba, Córdoba, Spain
| | - Manuel Ruiz-Rubio
- Department of Genetics, University of Córdoba, Córdoba, Spain
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), Córdoba, Spain
- University Hospital Reina Sofía of Córdoba, Córdoba, Spain
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11
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Richards G, Beking T, Kreukels BPC, Geuze RH, Beaton AA, Groothuis T. An examination of the influence of prenatal sex hormones on handedness: Literature review and amniotic fluid data. Horm Behav 2021; 129:104929. [PMID: 33454315 DOI: 10.1016/j.yhbeh.2021.104929] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 01/27/2023]
Abstract
Competing theories have posited roles for foetal androgen exposure in the development of human handedness. However, due to practical and ethical considerations, few studies have used hormonal measures to examine this possibility. The current paper reviews this literature and reveals a generally inconsistent pattern of results. We also present data from a longitudinal study of prenatal sex hormone exposure and subsequent handedness. More specifically, we examine correlations between testosterone and estradiol measured from second trimester amniotic fluid and hand preference (Dutch language version of the Edinburgh Handedness Inventory) and hand skill asymmetry (pegboard task) measured at 15 years of age. Prenatal sex hormone exposure was not associated with the direction of hand preference in either males or females. However, in females, high levels of prenatal testosterone were associated with weaker lateralisation of hand skill, and high levels of prenatal estradiol were associated with weaker hand preference. In addition, high levels of prenatal testosterone were associated with increased task duration (i.e., slow hand speed) for the right and left hands of males. The pattern of results observed here is not entirely consistent with any of the main theories linking sex hormones with handedness, suggesting that an association between these variables may be more complex than initially thought.
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Affiliation(s)
- Gareth Richards
- Newcastle University, School of Psychology, Ridley Building 1, Queen Victoria Road, Newcastle upon Tyne NE1 7RU, UK; University of Cambridge, Autism Research Centre, Department of Psychiatry, Douglas House, 18b Trumpington Road, Cambridge CB2 8AH, UK.
| | - Tess Beking
- University of Groningen, Faculty of Behavioural and Social Sciences, Department Clinical & Developmental Neuropsychology, Grote Kruisstraat 2/1, 9712 TS Groningen, the Netherlands; Amsterdam University Medical Center, location VUmc, Department of Medical Psychology, Center of Expertise on Gender Dysphoria, PO Box 7057, 1007 MB Amsterdam, the Netherlands; University of Groningen, Groningen Institute for Evolutionary Life Sciences, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Baudewijntje P C Kreukels
- Amsterdam University Medical Center, location VUmc, Department of Medical Psychology, Center of Expertise on Gender Dysphoria, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Reint H Geuze
- University of Groningen, Faculty of Behavioural and Social Sciences, Department Clinical & Developmental Neuropsychology, Grote Kruisstraat 2/1, 9712 TS Groningen, the Netherlands
| | - Alan A Beaton
- Swansea University, Department of Psychology, School of Human & Health Sciences, Swansea SA2 8PP, UK; Aberystwyth University, Department of Psychology, Aberystwyth SY23 3UX, UK
| | - Ton Groothuis
- University of Groningen, Groningen Institute for Evolutionary Life Sciences, Nijenborgh 7, 9747 AG Groningen, the Netherlands
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12
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Digit ratio, a proposed marker of the prenatal hormone environment, is not associated with prenatal sex steroids, anogenital distance, or gender-typed play behavior in preschool age children. J Dev Orig Health Dis 2020; 12:923-932. [PMID: 33336644 DOI: 10.1017/s2040174420001270] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Prenatal hormones have been proposed as key factors impacting child development as well as long-term health and disease. Digit ratio (the ratio of the lengths of the second to fourth digits; 2D:4D) has been proposed as a sexually dimorphic, noninvasive marker of prenatal androgen exposure that can be reliably measured in children and adults. To date, few longitudinal pregnancy cohort studies have examined childhood digit ratio in relation to other relevant measures including prenatal hormones and androgen-sensitive outcomes. To augment the current literature on this topic, we measured right-hand digit ratio in 4-year-old children participating in The Infant Development and the Environment Study, a multicenter longitudinal cohort study that has been following mother-child dyads since the first trimester of pregnancy (n = 321). We assessed sex differences in digit ratio and fit multivariable linear regression models to examine digit ratio in relation to: (1) child sex; (2) maternal sex steroid hormone concentrations in early pregnancy; (3) newborn anogenital distance, another proposed measure of sensitivity to prenatal androgens; and (4) gender-typical play behavior as measured by the Preschool Activities Inventory (PSAI) at age 4. We observed no sex difference in digit ratio; the mean 2D:4D was 0.97 ± 0.05 mm in both sexes. Furthermore, digit ratio was not associated with maternal sex steroid concentrations in early pregnancy, anogenital distance in either sex, or PSAI scores in either sex in covariate-adjusted models. In conclusion, we observed no evidence that early childhood digit ratio was associated with child sex or hormone-sensitive measures in this cohort.
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Baxter A, Wood EK, Witczak LR, Bales KL, Higley JD. Sexual Dimorphism in Titi Monkeys' Digit (2D:4D) Ratio is Associated with Maternal Urinary Sex Hormones During Pregnancy. Dev Psychobiol 2020; 62:979-991. [PMID: 31372988 PMCID: PMC7871332 DOI: 10.1002/dev.21899] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/15/2019] [Accepted: 06/28/2019] [Indexed: 12/23/2022]
Abstract
The second-to-fourth digit (2D:4D) ratio is a sexually-dimorphic biomarker for prenatal sex hormone exposure. We investigated whether titi monkeys (Plecturocebus cupreus) exhibit sexually-dimorphic 2D:4D ratio, and whether variation in 2D:4D ratio correlates with maternal testosterone and estrogen levels during early pregnancy. Subjects were 61 adult titi monkeys (32 males, 29 females). For 26 subjects, maternal urine samples were collected approximately 15-20 weeks before birth and assayed for testosterone and estrone conjugate (E1 C). Titi monkeys exhibited a human-like pattern of sexual dimorphism in right-hand 2D:4D ratio, with females exhibiting higher 2D:4D ratio than males (β = -0.29, p = 0.023). For left-hand 2D:4D ratio, high levels of maternal E1 C predicted low offspring 2D:4D ratio (β = -0.48, p = 0.009). For right-hand 2D:4D ratio, high levels of testosterone (β = -0.53, p = 0.005) and testosterone-to-E1 C ratio (β = -0.41, p = 0.028) predicted low offspring 2D:4D ratio. For 2D:4D ratio asymmetry (right-hand - left-hand), high levels of testosterone (β = -0.43, p = 0.03) and testosterone-to-E1 C ratio (β = -0.53, p = 0.003) predicted low (right-biased) asymmetry. This is the first report of sexually-dimorphic 2D:4D ratio in New World monkeys, and the results support a growing literature suggesting prenatal sex hormones may modulate offspring 2D:4D ratio.
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Affiliation(s)
- Alexander Baxter
- Department of Psychology, Brigham Young University, Provo, Utah
- Department of Psychology, University of California, Davis, California
- California National Primate Research Center, Davis, California
| | | | - Lynea R Witczak
- Department of Psychology, University of California, Davis, California
- California National Primate Research Center, Davis, California
| | - Karen L Bales
- Department of Psychology, University of California, Davis, California
- California National Primate Research Center, Davis, California
| | - J Dee Higley
- Department of Psychology, Brigham Young University, Provo, Utah
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Chen Y, Miao M, Liang H, Chen Y, Ji H, Ren Y, Liu X, Zhou Y, Wang Z, Yuan W. Effects of prenatal exposure to polybrominated diphenyl ethers (PBDEs) on the second to fourth digit ratio in children aged 4 years. Int J Hyg Environ Health 2020; 231:113639. [PMID: 33130430 DOI: 10.1016/j.ijheh.2020.113639] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 01/18/2023]
Abstract
BACKGROUND The second to fourth digit ratio (2D:4D) is assumed to be a biomarker of prenatal sex steroid exposure, correlating negatively with prenatal testosterone and positively with prenatal estrogen. The ratio has been suggested to be influenced by endocrine disrupting chemicals (EDCs). However, evidence regarding effects of prenatal exposure to polybrominated diphenyl ethers (PBDEs) on 2D:4D of children was sparse. OBJECTIVES We investigated the associations between prenatal exposure to PBDEs and 2D:4D of children aged 4 years. METHODS Participants were mother-child pairs from the Shanghai-Minhang Birth Cohort Study (S-MBCS) which enrolled pregnant women at 12-16 weeks of gestation from April to December 2012. Nine PBDE congeners in venous umbilical cord plasma of 340 children were measured. Digit lengths were measured using a vernier caliper in children aged 4 years and 2D:4D for left and right hands and average 2D:4D value of both hands were calculated. A total of 281 children (160 boys and 121 girls) who had data on both 2D:4D and PBDE concentrations were included in the final analysis. Associations between prenatal PBDE exposures and 2D:4D were investigated using multiple linear regression models. RESULTS Among the nine congeners, BDE-47 had the highest detection rate of 86.12% with the highest median concentration of 0.20 ng/ml lipid. Five PBDE congeners with detection rates greater than or close to 50% (BDE-28, -47, -99, -100 and -153) and Σ5PBDEs (the sum of them) were included in final analysis. For girls, a consistent pattern for the positive associations between prenatal PBDE exposures and 2D:4D of children was observed mainly for the left hand, where those in the highest exposure groups had higher 2D:4D compared to the lowest exposure groups (a feminizing effect), with statistically significant associations observed for BDE-47 (β = 0.0247, 95% confidence interval (CI): 0.0017, 0.0477), -100 (β = 0.0264, 95% CI: 0.0087, 0.0441) and Σ5PBDEs (β = 0.0201, 95% CI: 0.0027, 0.0374). For boys, compared with the lowest exposure groups, statistically significantly higher (feminized) 2D:4D for both hands was observed in those with the highest exposure levels of BDE-100 (β = 0.0147, 95% CI: 0.0005, 0.0289 for the left hand; β = 0.0182, 95% CI: 0.0046, 0.0318 for the right hand) and those with the middle and the highest exposure levels of BDE-153 (middle vs. undetected, β = 0.0215, 95% CI: 0.0072, 0.0358 for the left hand; β = 0.0155, 95% CI: 0.0015, 0.0295 for the right hand; highest vs. undetected, β = 0.0162, 95% CI: 0.0017, 0.0307 for the left hand; β = 0.0152, 95% CI: 0.0011, 0.0294 for the right hand). CONCLUSIONS Our study provides preliminary evidence that prenatal exposure to PBDEs might be associated with higher 2D:4D in boys and girls.
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Affiliation(s)
- Yafei Chen
- NHC Key Lab. of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), School of Public Health, Fudan University, China
| | - Maohua Miao
- NHC Key Lab. of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), School of Public Health, Fudan University, China
| | - Hong Liang
- NHC Key Lab. of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), School of Public Health, Fudan University, China
| | - Yao Chen
- NHC Key Lab. of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), School of Public Health, Fudan University, China
| | - Honglei Ji
- NHC Key Lab. of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), School of Public Health, Fudan University, China
| | - Yanfeng Ren
- Department of Health Statistics, School of Public Health and Management, Weifang Medical University, Shandong, China
| | - Xiao Liu
- Hubei Provincial Key Laboratory of Applied Toxicology, National Reference Laboratory of Dioxin, Hubei Provincial Center for Disease Control and Prevention, Wuhan, China
| | - Yan Zhou
- Hubei Provincial Key Laboratory of Applied Toxicology, National Reference Laboratory of Dioxin, Hubei Provincial Center for Disease Control and Prevention, Wuhan, China
| | - Ziliang Wang
- NHC Key Lab. of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), School of Public Health, Fudan University, China.
| | - Wei Yuan
- NHC Key Lab. of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), School of Public Health, Fudan University, China
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15
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Körner LM, Schaper ML, Pause BM, Heil M. Parent-Reports of Sex-Typed Play Preference in Preschool Children: Relationships to 2D:4D Digit Ratio and Older Siblings' Sex. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:2715-2724. [PMID: 32222854 PMCID: PMC7497428 DOI: 10.1007/s10508-020-01662-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 05/06/2023]
Abstract
Sex-typed play behavior shows large sex differences and seems to be affected by prenatal sex hormones. For example, a smaller, more male-typical ratio between the second and fourth digit length (2D:4D), a proposed marker for prenatal testosterone exposure, has been shown to be related to sex-typed play preference in childhood. Nevertheless, it is still being debated whether 2D:4D displays a stable sex difference throughout childhood, as there are few longitudinal studies. In the present study, children's 2D:4D was measured on both hands on four occasions from early infancy to early childhood (T1: 5 months, T2: 9 months, T3: 20 months, and T4: 40 months) providing the rare possibility to test the temporal stability of the sex difference. Parents completed the Preschool Activities Inventory at T4 and reported on the number of older brothers and sisters as a measure for socialization influences. Parents described boys as playing more masculine and less feminine than girls. Boys had smaller 2D:4D than girls at all measurements (T1-T4) and on both hands (right/left). Nevertheless, 2D:4D increased significantly from T3 to T4 in both sexes. Girls, but not boys, who were described as playing more masculine and less feminine had more masculine 2D:4D ratios at T1-T4 on both hands (except for right 2D:4D at T2 and T3) and had more older brothers and fewer older sisters. These data underline the stability of the sex difference in 2D:4D and show the importance of both biological and social influences on sex-typed play behavior.
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Affiliation(s)
- Lisa M Körner
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
| | - Marie Luisa Schaper
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Bettina M Pause
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Martin Heil
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
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16
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Asymmetric Behavior in Ptyodactylus guttatus: Can a Digit Ratio Reflect Brain Laterality? Symmetry (Basel) 2020. [DOI: 10.3390/sym12091490] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The digit ratio, an indicator of brain laterality, is the ratio of the second and fourth digits on the left (L24) or right foot (R24). Much of the research on the digit ratio and brain laterality focuses on primates, rather than other species such as reptiles. We tested whether the digit ratio in the gecko Ptyodactylus guttatus was associated with behaviors attributed to brain laterality. We examined risk-taking behavior (time spent under cover), foot preference (which foot was the first to start moving) and the side from which geckos bypassed an obstacle, in relation to the digit ratio. Geckos with longer fourth digits on their left hind foot (higher digit ratio) spent more time under cover. Geckos starting to move with their left leg were much more likely to bypass obstacles from the right side, and vice versa. This is the first evidence of laterality being associated with the digit ratio in reptiles. Comparisons among vertebrates are needed in order to decipher the evolutionary origin of the commonalities and peculiarities of brain asymmetry and disentangle the patterns and drivers of our evolutionary tree.
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17
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Jones AL, Satchell LP, Jaeger B, Schild C. (Mis-)understanding COVID-19 and digit ratio: Methodological and statistical issues in Manning and Fink (2020). Early Hum Dev 2020; 148:105095. [PMID: 32499091 PMCID: PMC7256504 DOI: 10.1016/j.earlhumdev.2020.105095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 05/26/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Alex L. Jones
- Department of Psychology, Swansea University, UK,Corresponding author.
| | | | - Bastian Jaeger
- Department of Social Psychology, Tilburg University, Netherlands
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18
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Mason KA, Schoelwer MJ, Rogol AD. Androgens During Infancy, Childhood, and Adolescence: Physiology and Use in Clinical Practice. Endocr Rev 2020; 41:5770947. [PMID: 32115641 DOI: 10.1210/endrev/bnaa003] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 02/28/2020] [Indexed: 12/29/2022]
Abstract
We provide an in-depth review of the role of androgens in male maturation and development, from the fetal stage through adolescence into emerging adulthood, and discuss the treatment of disorders of androgen production throughout these time periods. Testosterone, the primary androgen produced by males, has both anabolic and androgenic effects. Androgen exposure induces virilization and anabolic body composition changes during fetal development, influences growth and virilization during infancy, and stimulates development of secondary sexual characteristics, growth acceleration, bone mass accrual, and alterations of body composition during puberty. Disorders of androgen production may be subdivided into hypo- or hypergonadotropic hypogonadism. Hypogonadotropic hypogonadism may be either congenital or acquired (resulting from cranial radiation, trauma, or less common causes). Hypergonadotropic hypogonadism occurs in males with Klinefelter syndrome and may occur in response to pelvic radiation, certain chemotherapeutic agents, and less common causes. These disorders all require testosterone replacement therapy during pubertal maturation and many require lifelong replacement. Androgen (or gonadotropin) therapy is clearly beneficial in those with persistent hypogonadism and self-limited delayed puberty and is now widely used in transgender male adolescents. With more widespread use and newer formulations approved for adults, data from long-term randomized placebo-controlled trials are needed to enable pediatricians to identify the optimal age of initiation, route of administration, and dosing frequency to address the unique needs of their patients.
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Affiliation(s)
- Kelly A Mason
- Department of Pediatrics, University of Virginia, Charlottesville, Virginia
| | | | - Alan D Rogol
- Department of Pediatrics, University of Virginia, Charlottesville, Virginia
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19
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Sadr M, Khorashad BS, Talaei A, Fazeli N, Hönekopp J. 2D:4D Suggests a Role of Prenatal Testosterone in Gender Dysphoria. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:421-432. [PMID: 31975034 PMCID: PMC7031197 DOI: 10.1007/s10508-020-01630-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 01/03/2020] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
Gender dysphoria (GD) reflects distress caused by incongruence between one's experienced gender identity and one's natal (assigned) gender. Previous studies suggest that high levels of prenatal testosterone (T) in natal females and low levels in natal males might contribute to GD. Here, we investigated if the 2D:4D digit ratio, a biomarker of prenatal T effects, is related to GD. We first report results from a large Iranian sample, comparing 2D:4D in 104 transwomen and 89 transmen against controls of the same natal sex. We found significantly lower (less masculine) 2D:4D in transwomen compared to control men. We then conducted random-effects meta-analyses of relevant studies including our own (k = 6, N = 925 for transwomen and k = 6, N = 757 for transmen). In line with the hypothesized prenatal T effects, transwomen showed significantly feminized 2D:4D (d ≈ 0.24). Conversely, transmen showed masculinized 2D:4D (d ≈ - 0.28); however, large unaccounted heterogeneity across studies emerged, which makes this effect less meaningful. These findings support the idea that high levels of prenatal T in natal females and low levels in natal males play a part in the etiology of GD. As we discuss, this adds to the evidence demonstrating the convergent validity of 2D:4D as a marker of prenatal T effects.
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Affiliation(s)
- Mostafa Sadr
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Behzad S Khorashad
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Talaei
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Nasrin Fazeli
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Johannes Hönekopp
- Department of Psychology, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK.
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20
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Paukner A. Digit ratio (2D:4D) and its behavioral correlates in infant rhesus macaques (Macaca mulatta). Dev Psychobiol 2019; 62:992-998. [PMID: 31512755 DOI: 10.1002/dev.21917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 08/16/2019] [Accepted: 08/17/2019] [Indexed: 11/11/2022]
Abstract
2D:4D ratios are typically lower in adult human males than females and are linked to numerous sex-differentiated behaviors. 2D:4D ratios are considered an indicator of prenatal androgen exposure; if so, children's 2D:4D ratios would arguably be even better indicators of prenatal androgen exposure since children have experienced fewer postnatal influences than adults. However, sex differences in 2D:4D ratios as well as associations between 2D:4D ratios and sex-typed behaviors in children have been inconsistent. Several studies also report sex differences and behavioral correlates of 2D:4D ratios in adult non-human primates, but little is known about 2D:4D ratios in infant non-human primates. This study examined sex differences in 2D:4D ratios over the first month of life, and associations with behavioral outcomes at 12-24 weeks of age, in N = 304 infant rhesus macaques. An increase in 2D:4D ratios over the first month of life was found, as well as associations with aggression and play behaviors, but no sex differences in 2D:4D ratios were observed. These results highlight the need for future developmental studies of 2D:4D ratios in order to determine not only their stability and predictive value, but also to discern the mechanism connecting prenatal androgen exposure, 2D:4D ratios, and behavioral outcomes.
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Affiliation(s)
- Annika Paukner
- Psychology Department, Nottingham Trent University, Nottingham, UK
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21
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Yuksel T, Sizer E, Durak H. 2D:4D ratios as an indicator of intrauterine androgen exposure in children who stutter. Early Hum Dev 2019; 135:27-31. [PMID: 31228858 DOI: 10.1016/j.earlhumdev.2019.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 11/15/2022]
Abstract
AIM We aimed to explore whether there is a relationship between stuttering and digit ratio (2D:4D), which is thought to be a marker of prenatal testosterone exposure. METHODS We evaluated a total of 90 children who stutter (CWS; n = 40 mild-to-moderate and n = 50 severe stutters) and 40 healthy peers (CWNS) as controls. We used the Clinical Global Impression-Severity (CGIS) scale to measure the severity of stuttering. We measured the lengths of index finger (2D) and ring finger (4D) of both hands directly and divided to calculate 2D:4D ratio. The difference between the right and the left hand 2D:4D ratio (DR-L) was also calculated. RESULT Significant difference was found in right 2D:4D and the mean DR-L between the CWS and CWNS groups. Right 2D:4D was significantly lower in stuttering boys than in control boys, and in stuttering girls than control girls. Also, DR-L was significantly lower in stuttering boys than control boys. In ANOVA, there were significant differences between the mild-to-moderate, severe stuttering and control groups in terms of right 2D:4D and DR-L. Right hand 2D:4D and DR-L decreased from controls to severe stutterers. CONCLUSION Our results suggest that lower right 2D:4D and DR-L were related to the presence and severity of stuttering in children, i.e. CWS had lower 2D:4D and DR-L than CWNS. Further large-scale prospective studies are needed to clarify the reliability of 2D:4D ratio as an indicator of fetal sex hormone exposure level and its relation with the presence and severity of stuttering in children.
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Affiliation(s)
- Tugba Yuksel
- Dicle University School of Medicine, Department of Child and Adolescent Psychiatry, Diyarbakir, Turkey.
| | - Esra Sizer
- Dicle University School of Medicine, Department of Child and Adolescent Psychiatry, Diyarbakir, Turkey
| | - Hasan Durak
- Dicle University School of Medicine, Department of Child and Adolescent Psychiatry, Diyarbakir, Turkey
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22
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Wong WI, Yeung SP. Early Gender Differences in Spatial and Social Skills and Their Relations to Play and Parental Socialization in Children from Hong Kong. ARCHIVES OF SEXUAL BEHAVIOR 2019; 48:1589-1602. [PMID: 31123945 DOI: 10.1007/s10508-019-1415-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 01/31/2019] [Accepted: 02/02/2019] [Indexed: 05/26/2023]
Abstract
Children's play preferences are highly gender-typed. At the same time, much research revolves around spatial and social skills that sometimes show male and female advantages, respectively. There is evidence that play with masculine toys is associated with better spatial skills and emerging evidence suggests that play with feminine toys is associated with better social skills. However, several research gaps limit current knowledge on these aspects of gender development. First, the study of childhood gender development has been largely Eurocentric; second, the link between gender-typed play and social skills development is not well supported. We tested 644 5-year-old Hong Kong Chinese children on five gender-typed skills, play preferences, and parental gender socialization. The pattern of gender differences was remarkably similar to those in the West. Boys preferred masculine toys more than girls and were better at mental transformation and targeting accuracy, while girls preferred feminine (and neutral) toys more than boys and were better at empathy and were less aggressive, although there was no significant gender difference in comforting skill. There was little evidence that these gender differences varied with socioeconomic status (parental income and education). Play correlated with some outcomes in expected ways. This is in contrast to parents' gender socialization, which showed some expected differences by child gender but minimally correlated with children's skills. These findings shed light on the generalizability of current knowledge on early gender differences and may facilitate gender developmental research outside the West. Although the study did not test the direction of effects, they substantiate the growing discourse on gender-typed play as an important learning mechanism.
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Affiliation(s)
- Wang Ivy Wong
- Department of Psychology, University of Hong Kong, Pokfulam, Hong Kong.
- Gender Studies Program, The Chinese University of Hong Kong, Sino Building, Shatin, N.T., Hong Kong.
| | - Sui Ping Yeung
- Department of Psychology, University of Hong Kong, Pokfulam, Hong Kong
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Králík M, Hupková A, Zeman T, Hložek M, Hlaváček L, Slováčková M, Čuta M, Urbanová P. Family effects on the digit ratio (2D:4D): The role of the interbirth interval. Am J Hum Biol 2019; 31:e23260. [PMID: 31183942 DOI: 10.1002/ajhb.23260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/26/2019] [Accepted: 05/12/2019] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVES Family represents the closest social environment that immediately affects human ontogeny from an early prenatal period. This study aimed to assess sibship influences on the second-to-fourth digit length ratio (2D:4D ratio). METHODS The source sample represented 329 children aged 6.5 to 15.8 years (Czech Republic), including a subsample of 75 sibling pairs. A combination of (a) between-family design (cross-sectional sample) and (b) within-family design (pairs of siblings) was used to study the effect of family variables and interbirth interval (IBI) on the 2D:4D ratio. RESULTS Birth order, number of siblings (except for younger sisters), and sex ratio in siblings were significantly related to the 2D:4D ratio on the right, left, or both hands. At the same time, the relationships were opposite in males and females for birth order, number of older brothers and number of children in the family--increasing values in these variables increased digit ratio in males but decreased digit ratio in females. Mean difference in 2D:4D ratio (DIFF) within pairs (older minus younger sibling) differed from zero only in the "older sister--younger brother" group, where DIFF did not depend on IBI. On the contrary, in remaining pair types the DIFF tended to change with IBI, the strongest in the "older brother--younger sister" pairs. CONCLUSIONS Family variables, especially number of older brothers, should be considered as important confounding factors in 2D:4D ratio studies. However, the effect of these variables might be modified by IBI.
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Affiliation(s)
- Miroslav Králík
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Adela Hupková
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Tomáš Zeman
- Laboratory of Neurobiology and Molecular Psychiatry, Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Martin Hložek
- Department of Archaeology and Museology, Faculty of Arts, Masaryk University, Brno, Czech Republic
| | - Lukáš Hlaváček
- Palacký University Olomouc, Conference Services, Olomouc, Czech Republic
| | - Marie Slováčková
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Martin Čuta
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Petra Urbanová
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
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Roshan GM, Talaei A, Sadr M, Arezoomandan S, Kazemi S, Khorashad BS. Recalled pre-school activities among adults with gender dysphoria who seek gender confirming treatment-An Iranian study. Asian J Psychiatr 2019; 42:57-61. [PMID: 30954930 DOI: 10.1016/j.ajp.2019.03.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 11/25/2022]
Abstract
Preschool play behaviors have been frequently shown to be associated with prenatal androgens. It has also been proposed that incongruent sex-typed play behaviors in childhood is associated with gender dysphoria in adulthood in both men and women. Most of these studies, however, have been conducted in western countries. In this study, we investigated the recalled childhood play behavior among a total number of 339 Iranian participants (n = 72 transwomen, n = 92 transmen, n = 75 cisgender men and n = 100 cisgender women) using Preschool Activity Inventory (PSAI). We found that PSAI mean scores of the four groups were significantly different (F(3,335 = 223.5, p < 0.001)). Both transmen and cisgender men scored significantly more masculine than transwomen and cisgender women but had no different with each other. Transwomen scored significantly more feminine than cisgender men and cisgender women. Our findings are in line with previous studies that suggest gender nonconforming play behaviors may be associated with gender dysphoria in adulthood. It also emphasizes the importance of this finding for in non-western clinical context and its implications.
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Affiliation(s)
- Ghasem M Roshan
- Transgender Studies Center, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Ali Talaei
- Transgender Studies Center, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Mostafa Sadr
- Transgender Studies Center, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Sanaz Arezoomandan
- Transgender Studies Center, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Sepideh Kazemi
- Transgender Studies Center, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Behzad S Khorashad
- Transgender Studies Center, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; School of Sport, Exercise, and Health Sciences, Loughborough University, UK.
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25
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Hoskin AW, Meldrum RC. The association between fetal testosterone and violent behavior: Additional evidence using the 2D:4D digit ratio. PERSONALITY AND INDIVIDUAL DIFFERENCES 2018. [DOI: 10.1016/j.paid.2018.06.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Khorashad BS, Roshan GM, Reid AG, Aghili Z, Moghadam MD, Khazai B, Hiradfar M, Afkhamizadeh M, Ghaemi N, Talaei A, Abbaszadegan MR, Aarabi A, Dastmalchi S, Van de Grift TC. Childhood Sex-Typed Behavior and Gender Change in Individuals with 46,XY and 46,XX Disorders of Sex Development: An Iranian Multicenter Study. ARCHIVES OF SEXUAL BEHAVIOR 2018; 47:2287-2298. [PMID: 30128981 DOI: 10.1007/s10508-018-1281-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 01/23/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Disorders of sex development (DSD) are congenital conditions in which the typical genetic and hormonal profiles are affected and thereby the usual process of sexual differentiation. Most of these studies, however, have been conducted in Western countries. In the present study, preschool sex-typed activities of Iranian individuals with DSD and their age-matched non-affected male and female relatives were assessed using the Pre-School Activities Inventory (PSAI) modified for retrospective self-report. A total of 192 individuals participated in our study, including 33 46,XX individuals with congenital adrenal hyperplasia (CAH; M age = 10.36, SD = 5.52), 15 46,XY individuals with complete androgen insensitivity syndrome (CAIS; M age = 19.8, SD = 7.14), and 16 46,XY individuals with 5-alpha reductase deficiency type-2 (5α-RD-2; M age = 17.31, SD = 7.28), as well as one age-matched non-affected male and female relative for each patient. With regard to PSAI scores, male-identifying participants with 5α-RD-2 and male controls reported similar levels of male-typical childhood play. Female-identifying participants with 5α-RD-2 and CAH showed comparable scores: significantly less masculine and more feminine than male controls, but significantly more masculine and less feminine than females with CAIS and female controls. These findings support the role of androgens in the development of sex-typical childhood play behavior, with those being exposed to higher levels of fetal functional androgens expressing more masculine behavior at preschool ages.
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MESH Headings
- 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/deficiency
- 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/genetics
- 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/metabolism
- Adolescent
- Adrenal Hyperplasia, Congenital/genetics
- Adrenal Hyperplasia, Congenital/metabolism
- Adrenal Hyperplasia, Congenital/physiopathology
- Adult
- Androgen-Insensitivity Syndrome/genetics
- Androgen-Insensitivity Syndrome/metabolism
- Androgen-Insensitivity Syndrome/physiopathology
- Androgens/metabolism
- Child
- Child Behavior
- Child, Preschool
- Disorder of Sex Development, 46,XY/genetics
- Disorder of Sex Development, 46,XY/metabolism
- Disorder of Sex Development, 46,XY/physiopathology
- Female
- Gender Identity
- Humans
- Hypospadias/genetics
- Hypospadias/metabolism
- Hypospadias/physiopathology
- Iran
- Male
- Retrospective Studies
- Self Report
- Sex Characteristics
- Sex Differentiation
- Sexual Development
- Steroid Metabolism, Inborn Errors/genetics
- Steroid Metabolism, Inborn Errors/metabolism
- Steroid Metabolism, Inborn Errors/physiopathology
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Affiliation(s)
- Behzad S Khorashad
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Ghasem M Roshan
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Alistair G Reid
- Molecular Pathology Unit, Liverpool Clinical Laboratories, Liverpool, UK
| | - Zahra Aghili
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Behnaz Khazai
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehran Hiradfar
- Department of Pediatric Surgery, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mozhgan Afkhamizadeh
- Endocrine Research Center, Department of Endocrinology, Iman Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Nosrat Ghaemi
- School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Talaei
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Reza Abbaszadegan
- Division of Human Genetics, Immunology Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Azadeh Aarabi
- Division of Human Genetics, Immunology Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Samira Dastmalchi
- Faculty of Psychology, Islamic Azad University, Torbat-e-Jam Branch, Torbat-e-Jam, Iran
| | - Tim C Van de Grift
- Department of Medical Psychology (Gender and Sexology), VU University Medical Center, Amsterdam, The Netherlands
- Department of Plastic, Reconstructive and Hand Surgery, VU University Medical Center, Amsterdam, The Netherlands
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27
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Shere M, Arbuckle TE, Monnier P, Fraser W, Velez MP. Time-to-pregnancy and offspring finger-length ratio (2D:4D). Am J Hum Biol 2018; 30:e23176. [PMID: 30329191 DOI: 10.1002/ajhb.23176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/28/2018] [Accepted: 08/01/2018] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES Time-to-Pregnancy (TTP) is an epidemiological tool to assess couple fecundity. The finger digit ratio (2D:4D) has been suggested as a marker of androgen exposure in utero. Maternal, paternal, or couple-mediated factors related to fecundity may also have an effect on androgen exposure during pregnancy. We aimed to investigate the association between TTP, infertility, or use of Assisted Reproductive Technologies (ART) and offspring 2D:4D. METHODS Data from 673 mother-child pairs were collected from questionnaires in the Maternal-Infant Research on Environmental Chemicals (MIREC) study across 10 cities in Canada. The mean maternal age was 33.4 years (SD 4.7), with a median gestational age of 12.1 weeks (SD 1.3), at the time of recruitment. Our study included 338 girls and 335 boys, and the mean age of the children at follow-up was 3.5 years (SD 1.0). TTP was assessed through questionnaires during the first trimester of pregnancy. Digital photographs of both hands were taken in a follow-up study to calculate the children's 2D:4D (2-5 years). anova, t tests, and multiple linear regression analyses were conducted. RESULTS Boys had significantly lower mean 2D:4Ds (0.936 ±0.041 in right hand, 0.936 ±0.040 in left hand) compared to girls (0.948 ±0.038 in right hand, 0.945 ±0.038 in left hand). The mean 2D:4D did not differ according to TTP, infertility, or use of ART. The only factors associated with the child's 2D:4D were the child's age and maternal 2D:4D. CONCLUSIONS Our study does not support an association between TTP, infertility, or use of ART and children's 2D:4D.
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Affiliation(s)
- Mahvash Shere
- School of Medicine, Queen's University, Kingston, Canada
| | - Tye E Arbuckle
- Targeted Epidemiology and Biomonitoring Section, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Ottawa, Canada
| | - Patricia Monnier
- Department of Obstetrics and Gynecology, McGill University Health Centre, Montreal, Canada
| | - William Fraser
- Sainte-Justine University Hospital Research Centre, University of Montreal, Montreal, Canada.,Department of Obstetrics and Gynecology, University of Sherbrooke, Quebec, Canada
| | - Maria P Velez
- Department of Obstetrics and Gynaecology, Division of Reproductive Endocrinology and Infertility, Queen's University, Kingston, Canada
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28
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Baxter A, Wood EK, Jarman P, Cameron AN, Capitanio JP, Higley JD. Sex Differences in Rhesus Monkeys' Digit Ratio (2D:4D Ratio) and Its Association With Maternal Social Dominance Rank. Front Behav Neurosci 2018; 12:213. [PMID: 30297989 PMCID: PMC6160532 DOI: 10.3389/fnbeh.2018.00213] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/27/2018] [Indexed: 01/30/2023] Open
Abstract
Prenatal androgen exposure (PAE) plays a pivotal role in masculinizing the developing body and brain, and extreme exposure may contribute to autism, anxiety disorder and schizophrenia. One commonly used biomarker for PAE is the pointer-to-ring-finger digit length (2D:4D) ratio. Although this biomarker is widely used in human studies, relatively few studies have investigated 2D:4D ratio in nonhuman primates, particularly rhesus macaques (Macaca mulatta), one of the most commonly used animals in biomedical research. Thus far, data suggest that sexual dimorphism in 2D:4D ratio may be in the opposite direction in some monkey species, when compared to the pattern exhibited by humans and great apes. Using a large sample size, we investigated whether rhesus monkeys' 2D:4D ratio shows the same sex-differentiated pattern present in other Old World monkey species. We also investigated whether individual differences in 2D:4D ratio are associated with the social dominance rank of subjects' mothers during pregnancy, and the social dominance rank the subjects attained as adults. Subjects were 335 rhesus monkeys between 3 years and 24 years of age (M = 6.6). Maternal dominance rank during pregnancy and subjects' adult dominance rank were categorized into tertiles (high, middle and low). Results showed that, across both hands, male rhesus monkeys exhibited higher 2D:4D ratio than females, a pattern consistent with other monkey species and a reversal from the pattern typically observed in humans and apes. This sex difference was modulated by maternal dominance rank, with female offspring of high-ranking and middle-ranking mothers exhibiting masculinized 2D:4D ratio, indicating that maternal dominance rank during pregnancy may influence levels of PAE. There was no association between subjects' 2D:4D ratio and the social dominance rank they attained as adults. These findings show a consistent sex difference in Old World monkeys' 2D:4D ratio that diverges from the pattern observed in apes and humans, and suggest maternal social dominance rank modulates PAE in rhesus monkeys.
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Affiliation(s)
- Alexander Baxter
- Department of Psychology, Brigham Young University, Provo, UT, United States
| | - Elizabeth K. Wood
- Department of Psychology, Brigham Young University, Provo, UT, United States
| | - Parker Jarman
- Department of Psychology, Brigham Young University, Provo, UT, United States
| | - Ashley N. Cameron
- California National Primate Research Center (CNPRC), Davis, CA, United States
| | - John P. Capitanio
- California National Primate Research Center (CNPRC), Davis, CA, United States
- Department of Psychology, University of California, Davis, Davis, CA, United States
| | - J. Dee Higley
- Department of Psychology, Brigham Young University, Provo, UT, United States
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29
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Horn L, Hungerländer NA, Windhager S, Bugnyar T, Massen JJM. Social status and prenatal testosterone exposure assessed via second-to-fourth digit ratio affect 6-9-year-old children's prosocial choices. Sci Rep 2018; 8:9198. [PMID: 29907777 PMCID: PMC6004003 DOI: 10.1038/s41598-018-27468-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 05/31/2018] [Indexed: 11/18/2022] Open
Abstract
Prosocial behaviour (i.e., voluntary behaviour intended to benefit another) seems to be fully developed in children by the age of 6 years. However, questions about which factors modify prosocial behaviour at that age remain understudied. Here we used a resource allocation paradigm to test prosocial behaviour in 6-9-year-old school children. They could decide between a "selfish" (i.e., one sticker for themselves) and a "prosocial" option (i.e., one sticker for themselves and one for the receiver) and we tested whether friendship, social status and prenatal androgen exposure (approximated by the 2nd to 4th digit ratio; 2D:4D) influenced children's prosocial choices. We found that children behaved prosocially, and that their prosocial tendencies were negatively correlated with prenatal androgen exposure; i.e., children with high 2D:4D ratios (reflecting low prenatal androgen exposure) acted more prosocially than children with low 2D:4D ratios. Further, their social status in the classroom influenced their choices: children with fewer interaction partners chose the "prosocial" option more often than more 'popular' children. However, they did so irrespectively of whether they were paired with a recipient or not. Our results highlight the importance of considering social, as well as physiological factors when investigating prosocial behaviour in children.
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Affiliation(s)
- Lisa Horn
- Department of Cognitive Biology, University of Vienna, Vienna, Austria.
| | | | - Sonja Windhager
- Department of Anthropology, University of Vienna, Vienna, Austria
- Department of Theoretical Biology, University of Vienna, Vienna, Austria
| | - Thomas Bugnyar
- Department of Cognitive Biology, University of Vienna, Vienna, Austria
| | - Jorg J M Massen
- Department of Cognitive Biology, University of Vienna, Vienna, Austria
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30
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Eichler A, Heinrich H, Moll GH, Beckmann MW, Goecke TW, Fasching PA, Muschler MR, Bouna-Pyrrou P, Lenz B, Kornhuber J. Digit ratio (2D:4D) and behavioral symptoms in primary-school aged boys. Early Hum Dev 2018; 119:1-7. [PMID: 29486372 DOI: 10.1016/j.earlhumdev.2018.02.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/12/2018] [Accepted: 02/14/2018] [Indexed: 10/18/2022]
Abstract
The second-to-forth digit length ratio (2D:4D) is considered to be a biomarker for intrauterine androgen levels. It is associated with adult and child mental health problems, primarily with behavioral symptoms and predominantly in males. Using a cross-sectional design, we examined whether 2D:4D was associated with conduct disorder (CD) symptoms in 138 primary-school aged children (54% boys, Mage = 7.70 years) and considered child sex as a moderating factor. Children's digit lengths were measured from hand scans and mothers rated the behavioral/emotional symptoms of their child. The regression analyses revealed that 2D:4D ratios were associated with behavioral symptoms in boys (β = -0.260, p = 0.026), but not in girls (β = -0.040, p = 0.762). Child emotional symptoms, analyzed as a control, were not significantly correlated with 2D:4D. In conclusion, prenatal brain hyperandrogenization - operationalized by the 2D:4D biomarker - could result in behavioral symptoms in boys at early school age, reflecting one predictor for early onset CD. Our data support the use of 2D:4D as a marker of prenatal androgen exposure.
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Affiliation(s)
- Anna Eichler
- Department of Child and Adolescent Mental Health, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 6+10, 91054 Erlangen, Germany.
| | - Hartmut Heinrich
- Department of Child and Adolescent Mental Health, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 6+10, 91054 Erlangen, Germany; kbo-Heckscher-Klinikum, Deisenhofener Str. 28, 81539 München, Germany
| | - Gunther H Moll
- Department of Child and Adolescent Mental Health, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 6+10, 91054 Erlangen, Germany
| | - Matthias W Beckmann
- Department of Obstetrics and Gynecology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 21-23, 91054 Erlangen, Germany
| | - Tamme W Goecke
- Department of Obstetrics and Gynecology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 21-23, 91054 Erlangen, Germany; Department of Perinatal Medicine and Obstetrics, RoMed Hospital Rosenheim, Pettenkoferstraße 10, 83022 Rosenheim, Germany
| | - Peter A Fasching
- Department of Obstetrics and Gynecology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 21-23, 91054 Erlangen, Germany
| | - Marcel-René Muschler
- Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054 Erlangen, Germany
| | - Polyxeni Bouna-Pyrrou
- Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054 Erlangen, Germany
| | - Bernd Lenz
- Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054 Erlangen, Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054 Erlangen, Germany
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The Association of Digit Ratio (2D : 4D) with Cancer: A Systematic Review and Meta-Analysis. DISEASE MARKERS 2018; 2018:7698193. [PMID: 29581795 PMCID: PMC5822871 DOI: 10.1155/2018/7698193] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/17/2017] [Accepted: 12/06/2017] [Indexed: 12/30/2022]
Abstract
Objective Intrauterine sex hormone environment as indicated by the second to the fourth digit ratio (2D : 4D) can be associated with cancer risk. This systematic review and meta-analysis aimed to evaluate the association of 2D : 4D with cancer diagnosis, malignancy, and age at presentation. Methods Studies that evaluated the association of 2D : 4D with cancer risk were collected from Pubmed/MEDLINE and Clarivate Analytics databases. Nineteen studies were included in the qualitative analysis. Results The 2D : 4D ratio was studied in prostate cancer, breast cancer, testicular cancer, gastric cancer, oral cancer, brain tumors, and cervical intraepithelial neoplasia. Low 2D : 4D was associated with prostate cancer, gastric cancer, and brain tumors, while high 2D : 4D, with breast cancer risk and cervical dysplasia. The 2D : 4D ratio was not associated with prostate, breast, and gastric cancer stage. Greater 2D : 4D ratio was associated with younger presentation of breast cancer and brain tumors. The meta-analyses demonstrated that testicular cancer was not associated with right-hand 2D : 4D ratio (p = 0.74) and gastric cancer was not associated with right-hand (p = 0.15) and left-hand (p = 0.95) 2D : 4D ratio. Conclusions Sex hormone environment during early development is associated with cancer risk later in life. Further studies exploring the link between intrauterine hormone environment and cancer risk are encouraged.
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Reinisch JM, Mortensen EL, Sanders SA. Prenatal Exposure to Progesterone Affects Sexual Orientation in Humans. ARCHIVES OF SEXUAL BEHAVIOR 2017; 46:1239-1249. [PMID: 28374065 DOI: 10.1007/s10508-016-0923-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 12/15/2016] [Accepted: 12/15/2016] [Indexed: 06/07/2023]
Abstract
Prenatal sex hormone levels affect physical and behavioral sexual differentiation in animals and humans. Although prenatal hormones are theorized to influence sexual orientation in humans, evidence is sparse. Sexual orientation variables for 34 prenatally progesterone-exposed subjects (17 males and 17 females) were compared to matched controls (M age = 23.2 years). A case-control double-blind design was used drawing on existing data from the US/Denmark Prenatal Development Project. Index cases were exposed to lutocyclin (bioidentical progesterone = C21H30O2; M W : 314.46) and no other hormonal preparation. Controls were matched on 14 physical, medical, and socioeconomic variables. A structured interview conducted by a psychologist and self-administered questionnaires were used to collect data on sexual orientation, self-identification, attraction to the same and other sex, and history of sexual behavior with each sex. Compared to the unexposed, fewer exposed males and females identified as heterosexual and more of them reported histories of same-sex sexual behavior, attraction to the same or both sexes, and scored higher on attraction to males. Measures of heterosexual behavior and scores on attraction to females did not differ significantly by exposure. We conclude that, regardless of sex, exposure appeared to be associated with higher rates of bisexuality. Prenatal progesterone may be an underappreciated epigenetic factor in human sexual and psychosexual development and, in light of the current prevalence of progesterone treatment during pregnancy for a variety of pregnancy complications, warrants further investigation. These data on the effects of prenatal exposure to exogenous progesterone also suggest a potential role for natural early perturbations in progesterone levels in the development of sexual orientation.
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Affiliation(s)
- June M Reinisch
- The Kinsey Institute for Research in Sex, Gender and Reproduction, Indiana University, Morrison Hall 313, Bloomington, IN, 47405, USA.
- The Museum of Sex, New York, NY, USA.
- Institute of Preventive Medicine, Copenhagen University Hospital, Copenhagen, Denmark.
| | - Erik Lykke Mortensen
- Institute of Preventive Medicine, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Stephanie A Sanders
- The Kinsey Institute for Research in Sex, Gender and Reproduction, Indiana University, Morrison Hall 313, Bloomington, IN, 47405, USA
- Department of Gender Studies, Indiana University, Bloomington, IN, USA
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Lu H, Shen D, Wang L, Niu S, Bai C, Ma Z, Huo Z. Digit ratio (2D:4D) and handgrip strength are correlated in women (but not in men) in Hui ethnicity. Early Hum Dev 2017; 109:21-25. [PMID: 28426948 DOI: 10.1016/j.earlhumdev.2017.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Digit ratio, especially second-to-fourth digit ratio (2D:4D) is used as a biomarker of prenatal testosterone exposure and was found associated with physical ability, such as handgrip strength (HGS). Recently, this association has been discussed in several ethnic groups. AIMS To investigate correlations between 2D:4D and HGS in Chinese population of Ningxia Hui ethnicity. METHODS Here we firstly present the evidence on digit ratio and HGS of 346 college students (119 males and 227 females) by collecting photographs and HGS of both hands at Yinchuan city, in the Ningxia province of China. RESULTS Females have higher mean values of digit ratio than males; significant variances of 3D:5D (left and right: P<0.05), 2D:3D, 3D:4D (left and right: P<0.01) and 2D:4D, 2D:5D (left and right: P<0.001) were found between different sex. Males showed significantly greater HGS than females on both hands. 2D:4D of both hands were significantly negative correlated with HGS in females (but not in males). CONCLUSIONS 2D:4D ratio is negatively correlated with HGS in a Chinese population (especially in females) of Ningxia Hui ethnicity.
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Affiliation(s)
- Hong Lu
- Ningxia Medical University, Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education/Key Laboratory of Reproduction and Genetics in Ningxia/Basic Medicine Science, Department of Medical Genetic and Cell Biology, Yinchuan 750004, PR China
| | - Dan Shen
- Ningxia Medical University, Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education/Key Laboratory of Reproduction and Genetics in Ningxia/Basic Medicine Science, Department of Medical Genetic and Cell Biology, Yinchuan 750004, PR China
| | - Lu Wang
- Clinical Medicine Science, Peking University Health Science Center, Beijing 100191, PR China
| | - Shibo Niu
- Ningxia Medical University, Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education/Key Laboratory of Reproduction and Genetics in Ningxia/Basic Medicine Science, Department of Medical Genetic and Cell Biology, Yinchuan 750004, PR China
| | - Chunyue Bai
- Ningxia Medical University, Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education/Key Laboratory of Reproduction and Genetics in Ningxia/Basic Medicine Science, Department of Medical Genetic and Cell Biology, Yinchuan 750004, PR China
| | - Zhanbing Ma
- Ningxia Medical University, Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education/Key Laboratory of Reproduction and Genetics in Ningxia/Basic Medicine Science, Department of Medical Genetic and Cell Biology, Yinchuan 750004, PR China
| | - Zhenghao Huo
- Ningxia Medical University, Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education/Key Laboratory of Reproduction and Genetics in Ningxia/Basic Medicine Science, Department of Medical Genetic and Cell Biology, Yinchuan 750004, PR China.
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Gray PB, McHale TS, Carré JM. A review of human male field studies of hormones and behavioral reproductive effort. Horm Behav 2017; 91:52-67. [PMID: 27449532 DOI: 10.1016/j.yhbeh.2016.07.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 05/12/2016] [Accepted: 07/17/2016] [Indexed: 02/06/2023]
Abstract
The purpose of this paper is to review field studies of human male hormones and reproductive behavior. We first discuss life history theory and related conceptual considerations. As illustrations, distinctive features of human male life histories such as coalitional aggression, long-term partnering and paternal care are noted, along with their relevance to overall reproductive effort and developmental plasticity. We address broad questions about what constitutes a human male field study of hormones and behavior, including the kinds of hormone and behavioral measures employed in existing studies. Turning to several sections of empirical review, we present and discuss evidence for links between prenatal and juvenile androgens and sexual attraction and aggression. This includes the proposal that adrenal androgens-DHEA and androstenedione-may play functional roles during juvenility as part of a life-stage specific system. We next review studies of adult male testosterone responses to competition, with these studies emphasizing men's involvement in individual and team sports. These studies show that men's testosterone responses differ with respect to variables such as playing home/away, winning/losing, and motivation. Field studies of human male hormones and sexual behavior also focus on testosterone, showing some evidence of patterned changes in men's testosterone to sexual activity. Moreover, life stage-specific changes in male androgens may structure age-related differences in sexual behavior, including decreases in sexual behavior with senescence. We overview the considerable body of research on male testosterone, partnerships and paternal care, noting the variation in social context and refinements in research design. A few field studies provide insight into relationships between partnering and paternal behavior and prolactin, oxytocin, and vasopressin. In the third section of the review, we discuss patterns, limitations and directions for future research. This includes discussion of conceptual and methodological issues future research might consider as well as opportunities for contributions in under-researched male life stages (juvenility, senescence) and hormones (e.g., vasopressin).
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Affiliation(s)
- Peter B Gray
- Department of Anthropology, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Box 455003, Las Vegas, NV 89154-5003, United States.
| | - Timothy S McHale
- Department of Anthropology, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Box 455003, Las Vegas, NV 89154-5003, United States
| | - Justin M Carré
- Department of Psychology, Nipissing University, 100 College Drive, North Bay, Ontario P1B 8L7, Canada
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Atkinson BM, Smulders TV, Wallenberg JC. An endocrine basis for tomboy identity: The second-to-fourth digit ratio (2D:4D) in "tomboys". Psychoneuroendocrinology 2017; 79:9-12. [PMID: 28242416 DOI: 10.1016/j.psyneuen.2017.01.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/27/2017] [Accepted: 01/27/2017] [Indexed: 12/01/2022]
Abstract
This paper investigates the relationship between organizational effects of pre-natal testosterone and the use of "tomboy" as a descriptor for young women. We show in a sample of 44 women that a woman's right hand 2D:4D ratio is a significant predictor of whether they will be labeled as a "tomboy", with a decrease in 2D:4D ratio corresponding to an increase in the probability of being called "tomboy". Taking the right hand 2D:4D ratio as a proxy for the abundance of testosterone in the early life hormonal milieu, we propose that organizing effects of higher pre-natal T lead to increased masculine-typical behavior in childhood, which increases the likelihood some women will be referred to as tomboys. We suggest that the increase in masculine-typical behaviors is a result of how the organizing effects of T on the brain interact with children's social modeling of male-coded and female-coded behaviors.
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Affiliation(s)
- Beth M Atkinson
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK.
| | - Tom V Smulders
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK.
| | - Joel C Wallenberg
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; School of English Literature, Language and Linguistics, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK.
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Wang LJ, Chou MC, Chou WJ, Lee MJ, Lee SY, Lin PY, Lee YH, Yang YH, Yen CF. Potential role of pre- and postnatal testosterone levels in attention-deficit/hyperactivity disorder: is there a sex difference? Neuropsychiatr Dis Treat 2017; 13:1331-1339. [PMID: 28553119 PMCID: PMC5439987 DOI: 10.2147/ndt.s136717] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE Both prenatal testosterone (T) exposure and postnatal T levels have been associated with developing neural circuitry and behavioral systems. This study examined the potential correlation between pre- and postnatal T levels and behavioral and neurocognitive profiles of children with attention-deficit/hyperactivity disorder (ADHD). METHODS Two hundred ADHD patients with a mean age of 8.7±2.0 years (158 boys and 42 girls) were recruited. The ratio of the length of the right index finger (2D) to that of the right ring finger (4D) (2D/4D ratio) served as a surrogate of prenatal T exposure, and postnatal T was determined using salivary T concentration. Behavioral symptoms were evaluated using the Swanson, Nolan, and Pelham - Version IV Scale for ADHD (SNAP-IV). Neurocognitive function was assessed using the Wechsler Intelligence Scale for Children - Fourth Edition (WISC-IV) and Conners' Continuous Performance Test (CPT). RESULTS Lower 2D/4D ratios were associated with comorbid disruptive behavior disorders (t=2.15, P=0.033) in all participants. Among the boys with ADHD, neither 2D/4D ratios nor salivary T levels were associated with behavioral symptoms or neurocognitive function. Among the girls with ADHD, the salivary T level was positively correlated with the Perceptual Reasoning Index of the WISC-IV (r=0.48, P=0.001) and the Confidence Index (r=0.37, P=0.017) and Omission Errors of the CPT (r=0.62, P<0.001). CONCLUSION Findings suggest that a higher prenatal T exposure is associated with a greater risk of developing disruptive behavior disorders, and T may exert differential neurocognitive effects between boys and girls with ADHD. However, the neurobiological mechanisms of T involved in the pathogenesis of ADHD warrant further investigation.
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Affiliation(s)
- Liang-Jen Wang
- Department of Child and Adolescent Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine.,Department of Psychiatry, School of Medicine, and Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University
| | - Miao-Chun Chou
- Department of Child and Adolescent Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine
| | - Wen-Jiun Chou
- Department of Child and Adolescent Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine
| | - Min-Jing Lee
- Department of Child and Adolescent Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine
| | - Sheng-Yu Lee
- Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung.,Department of Psychiatry, College of Medicine and Hospital, National Cheng Kung University, Tainan
| | - Pao-Yen Lin
- Department of Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine
| | - Yi-Hsuan Lee
- Department of Child and Adolescent Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine
| | - Yi-Hsin Yang
- School of Pharmacy, Kaohsiung Medical University Hospital
| | - Cheng-Fang Yen
- Department of Psychiatry, School of Medicine, and Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University.,Department of Psychiatry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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Shen D, Ma Z, Wang L, Huo Z, Lu H, Zhao J, Qian W. Digit ratio (2D:4D) and handgrip strength in a Chinese population of Han ethnicity. Early Hum Dev 2016; 103:141-145. [PMID: 27685464 DOI: 10.1016/j.earlhumdev.2016.09.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/15/2016] [Accepted: 09/20/2016] [Indexed: 12/31/2022]
Abstract
BACKGROUND In humans, the relative lengths of the index finger to the ring finger (2D:4D) is a sexually dimorphic trait which correlated with prenatal sex steroids and has been increasingly used as a promising tool to evaluate the impact of prenatal hormone exposure in some traits, such as physical performance. Handgrip strength (HGS) is one potent index of physical ability and its relationship with 2D:4D ratio has been discussed in several ethnic groups. AIMS To investigate whether there is a correlation between 2D:4D ratio and HGS in Chinese college students of Ningxia Han ethnicity. METHODS 608 students (211 males and 397 females) of Han ethnicity were recruited from Ningxia medical university. Photocopies and HGS of both hands were collected at Yinchuan city, in the Ningxia province of China. RESULTS Sexual dimorphism of 2D:4D and HGS were found, males had significantly lower 2D:4D and greater HGS than females. 2D:4D in both hands were significantly negative correlated with HGS in females and not in males. CONCLUSIONS 2D:4D ratio is negative correlated with HGS in a Chinese population of Ningxia Han ethnicity and this association should be considered on the anthropological research within an evolutionary concept in the future.
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Affiliation(s)
- Dan Shen
- Key Laboratory of Fertility Preservation, Maintenance of Ministry of Education, Ningxia Medical University/Key Laboratory of Reproduction and Genetics in Ningxia, Yinchuan 750004, PR China
| | - Zhanbing Ma
- Department of Medical Genetic and Cell Biology, Ningxia Medical University, Yinchuan 750004, PR China
| | - Lu Wang
- Clinical Medicine Science, Peking University Health Science Center, Beijing 100191, PR China
| | - Zhenghao Huo
- Key Laboratory of Fertility Preservation, Maintenance of Ministry of Education, Ningxia Medical University/Key Laboratory of Reproduction and Genetics in Ningxia, Yinchuan 750004, PR China; Department of Medical Genetic and Cell Biology, Ningxia Medical University, Yinchuan 750004, PR China
| | - Hong Lu
- Key Laboratory of Fertility Preservation, Maintenance of Ministry of Education, Ningxia Medical University/Key Laboratory of Reproduction and Genetics in Ningxia, Yinchuan 750004, PR China; Department of Medical Genetic and Cell Biology, Ningxia Medical University, Yinchuan 750004, PR China.
| | - Junli Zhao
- Medical Reproductive Center of General Hospital, Ningxia Medical University, Yinchuan 750004, PR China
| | - Wenli Qian
- Key Laboratory of Fertility Preservation, Maintenance of Ministry of Education, Ningxia Medical University/Key Laboratory of Reproduction and Genetics in Ningxia, Yinchuan 750004, PR China
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