Prenatal testosterone and gender-related behaviour

Giftedness and atypical sexual differentiation: enhanced perceptual functioning through estrogen deficiency instead of androgen excess

Syndromic autism spectrum conditions (ASC), such as Klinefelter syndrome, also manifest hypogonadism. Compared to the popular Extreme Male Brain theory, the Enhanced Perceptual Functioning model explains the connection between ASC, savant traits, and giftedness more seamlessly, and their co-emergence with atypical sexual differentiation. Overexcitability of primary sensory inputs generates a relative enhancement of local to global processing of stimuli, hindering the abstraction of communication signals, in contrast to the extraordinary local information processing skills in some individuals. Weaker inhibitory function through gamma-aminobutyric acid type A (GABAA) receptors and the atypicality of synapse formation lead to this difference, and the formation of unique neural circuits that process external information. Additionally, deficiency in monitoring inner sensory information leads to alexithymia (inability to distinguish one's own emotions), which can be caused by hypoactivity of estrogen and oxytocin in the interoceptive neural circuits, comprising the anterior insular and cingulate gyri. These areas are also part of the Salience Network, which switches between the Central Executive Network for external tasks and the Default Mode Network for self-referential mind wandering. Exploring the possibility that estrogen deficiency since early development interrupts GABA shift, causing sensory processing atypicality, it helps to evaluate the co-occurrence of ASC with attention deficit hyperactivity disorder, dyslexia, and schizophrenia based on phenotypic and physiological bases. It also provides clues for understanding the common underpinnings of these neurodevelopmental disorders and gifted populations.

Early prenatal sex steroids and sex-typed play behavior at 4 years of age

During pregnancy, estrogens and testosterone influence brain development, resulting in sex-typical behavioral phenotypes. Prenatal testosterone exposure is associated with more male-typical behaviors in rodents, monkeys, and humans; however, few studies have examined the relationship between maternal sex hormones within the normal range and sex-dimorphic behaviors. In this study, we examined associations between prenatal estrogens and testosterone and sex-typical play in The Infant Development and the Environment Study (TIDES), a multicenter pregnancy cohort. We collected prenatal serum during the first trimester (mean=11.1 ± 2.6 weeks) and assessed child play behavior using the maternally completed Pre-School Activities Inventory (PSAI) at a mean age of 4.5 ± 0.3 years. This analysis includes mother-child pairs with complete data on hormones, play behavior, and covariates (n = 192 boys and 207 girls). No associations were seen between testosterone and PSAI scores in boys or girls or between estrogens and PSAI scores in boys. In girls, we observed an inverse relationship between feminine PSAI scores and both estradiol (E2) and estriol (E3) in multivariable linear regression analyses (E2: -0.11 [95% CI -0.20, -0.02]; E3: -0.44 [95% CI -0.83,-0.04]). Because the relationship between sex hormones and PSAI scores appeared nonlinear, we fit piecewise regression models to better fit the data and identify inflection points (point at which there is a significant change in slope). Piecewise regression analyses yielded inverse associations between masculine PSAI scores and estrone (E1) at values of E1 > 1340 pg/mL and E2 at values of E2 > 2870 pg/mL in girls. Further studies are needed to better understand the role of prenatal sex steroids on sexually dimorphic behavior.

Investigation of the Causes of Negative Attitudes towards Women Incompatible with Gender Stereotypes within the Context of Social Identity Theory

The primary gender stereotypes accepted in mainstream social psychology describe women as low in competence and high in warmth, men as having low warmth and high competence. Women who are incompatible with stereotypes are exposed to negative attitudes. Exposure to negative attitudes damages the psychological well-being of these group members. Stereotypes and negative attitudes towards members of social groups contribute to the persistence of their low status. Explaining the causes of gender stereotypes and negative attitudes towards women incompatible with stereotypes is an overlooked topic in mainstream social psychology. In order to change the ongoing gender system, where women have a disadvantageous status compared to men, it is necessary to understand the reasons for negative attitudes towards women who are incompatible with stereotypes. Based on the suggestions and findings of Social Identity Theory, explanations about negative attitudes towards women who are incompatible with gender stereotypes are presented in this study. It is concluded that most men reveal negative attitudes towards these women because women with high competency threaten men who can affirm their social identity through competency. Most men define their social identity through status-related traits such as competency. Due to the threat to men's social identity by women with high competence, it is concluded that negative attitudes towards these women are revealed by most of the men, based on theoretical suggestions. It is necessary to understand the identity management strategies to explain women's negative attitudes towards their fellows who are incompatible with stereotypes. According to the theoretical suggestions and related studies, it is concluded that the adoption of individual mobility and social creativity strategies reveal negative attitudes toward fellows who are incompatible with stereotypes. Although it is expected that women who adopt the social competition strategy have positive attitudes towards their fellows who are inconsistent with gender stereotypes, the level of adoption of this strategy is low. When theoretical suggestions and study findings are brought together, it is possible to understand the reasons for the negative attitudes towards women who are incompatible with gender stereotypes.

Robust sex differences in functional brain connectivity are present in utero

Sex-based differences in brain structure and function are observable throughout development and are thought to contribute to differences in behavior, cognition, and the presentation of neurodevelopmental disorders. Using multiple support vector machine (SVM) models as a data-driven approach to assess sex differences, we sought to identify regions exhibiting sex-dependent differences in functional connectivity and determine whether they were robust and sufficiently reliable to classify sex even prior to birth. To accomplish this, we used a sample of 110 human fetal resting state fMRI scans from 95 fetuses, performed between 19 and 40 gestational weeks. Functional brain connectivity patterns classified fetal sex with 73% accuracy. Across SVM models, we identified features (functional connections) that reliably differentiated fetal sex. Highly consistent predictors included connections in the somatomotor and frontal areas alongside the hippocampus, cerebellum, and basal ganglia. Moreover, high consistency features also implicated a greater magnitude of cross-region connections in females, while male weighted features were predominately within anatomically bounded regions. Our findings indicate that these differences, which have been observed later in childhood, are present and reliably detectable even before birth. These results show that sex differences arise before birth in a manner that is consistent and reliable enough to be highly identifiable.

First Adolescent Romantic and Sexual Experiences in Individuals With Differences of Sex Development/Intersex Conditions

PURPOSE

Adolescence is an important period for sexual development, including sexual debut. The purpose of this study was to assess first romantic and sexual experiences and debut age in individuals with differences of sex development (DSD/intersex) and compare these with age-matched and gender-matched population control values.

METHODS

Questionnaire data on sociodemographic characteristics, romantic and sexual milestones (e.g., masturbation, dating), satisfaction with sexual life and sexual activity at follow-up, self-esteem, and feelings of femininity or masculinity were collected from 976 participants in Europe with a DSD condition. Participants were divided into six diagnostic subgroups based on their diagnostic classification: women with Turner syndrome, congenital adrenal hyperplasia, 46XY-DSD nonvirilized, and 46XY-DSD female partially virilized conditions and men with 46XY-DSD male or Klinefelter syndrome. Age-specific and gender-specific reference values were retrieved from a Dutch population sample.

RESULTS

Individuals with DSD were less likely to reach each of the romantic and sexual milestones compared to their peers without these conditions and they were significantly older when reaching these milestones. Between clinical subgroups, individuals with Klinefelter were significantly older when reaching milestones and in the female groups and individuals with Turner were the least likely to reach milestones. Furthermore, a higher age when reaching several romantic and sexual milestones was correlated with lower self-esteem, lower satisfaction with sexual life, and lower sexual frequency at follow-up.

DISCUSSION

Due to a difference in biopsychosocial context, individuals with DSD often experience a different and/or delayed sexual development during adolescence. Healthcare providers should be aware of these differences in adolescents with DSD and their sexual development to optimize affirmative counseling.

A systematic review of sex differences in rough and tumble play across non-human mammals

Abstract

It is widely believed that juvenile male mammals typically engage in higher rates of rough and tumble play (RTP) than do females, in preparation for adult roles involving intense physical competition between males. The consistency of this sex difference across diverse mammalian species has, however, not yet been systematically investigated, limiting our current understanding of its possible adaptive function. This review uses narrative synthesis to (i) evaluate the ubiquity of male-biased RTP across non-human mammals, (ii) identify patterns of variation within and between taxonomic groups, and (iii) propose possible predictors of variation in these differences, including methodological and socio-ecological factors, for investigation by future studies. We find that most species studied do exhibit higher rates or RTP in males than females, while female-biased RTP is rare. Sex differences are smaller and less consistent than expected, with many studies finding similar rates of RTP in males and females. We identify multiple potential socio-ecological predictors of variation in sex differences in RTP, such as intrasexual competition and dietary niche. However, variation is not strongly phylogenetically patterned, suggesting that methodological and environmental factors, such as sample size and play partner availability, are important to consider in future comparative analyses.

Significance statement

Rough and tumble play (RTP) is thought to be vital for developing physical skills necessary for aggressive competition in adulthood, explaining an apparently widespread sex difference in RTP in mammals whereby immature males are more likely to engage in this behaviour than females. However, no prior study has systematically investigated the extent to which a male bias in RTP is consistent across diverse mammalian species. We find that although RTP is commonly male biased, findings were highly variable both within- and between-species, and equal participation in RTP by males and females is more common than widely assumed. Our review suggests several potential predictors of variation in sex differences in RTP, particularly levels of intrasexual competition in both males and females. However, our findings also suggest the importance of considering methodological in addition to socio-ecological factors for future research.

2D:4D digit ratio and its relationship to BMI, sporting choices and physiological predispositions among women

The 2D:4D digit ratio has been established as a biomarker of the level of exposure to prenatal sex hormones’ balancebetween prenatal testosterone (PT) and estrogenne levels. Higher 2D:4D indicates lower PT exposure and vice versa. Data suggests that PT exposure is linked to a risk-taking attitude and physical aggressiveness, both of which are requirements in contact sport. A possible correlation between 2D:4D and human body mass index has also been identified. The aim of the study was to examine the relation between 2D:4D ratio and choice of sport. It was assumed that female soccer players who choose a contact sport would have a lower 2D:4D ratio (thus experiencing higher exposure to PT) than female volleyball players (selecting non-contact sport). The analysis was also aimed at identifying whether a correlation between prenatal testosterone level and BMI exists. The participant sample consisted of 103 women – 36 volleyball players, 33 soccer players and a control group (N=34). Measurements were collected in 2019–2020. The results suggest that 2D:4D was significantly different in women practicing various sports (contact and non-contact sports). Women engaged in contact sports had lower 2D:4D than women engaged in non-contact sports, and vice versa (p<0.05). 2D:4D correlated positively with BMI and body weight – the higher the 2D:4D ratio, the higher the BMI and body weight (and vice versa) (p<0.05). Low 2D:4D (high PT exposure) may predict the choice of more risky, aggressive contact sports, and vice versa. High 2D:4D may predict a higher BMI and body weight, and vice versa.

Lipid endocannabinoids in energy metabolism, stress and developmental programming

The endocannabinoid system (ECS) regulates brain development and function, energy metabolism and stress in a sex-, age- and tissue-dependent manner. The ECS comprises mainly the bioactive lipid ligands anandamide (AEA) and 2-aracdonoylglycerol (2-AG), cannabinoid receptors 1 and 2 (CB1 and CB2), and several metabolizing enzymes. The endocannabinoid tonus is increased in obesity, stimulating food intake and a preference for fat, reward, and lipid accumulation in peripheral tissues, as well as favoring a positive energy balance. Energy balance and stress responses share adaptive mechanisms regulated by the ECS that seem to underlie the complex relationship between feeding and emotional behavior. The ECS is also a key regulator of development. Environmental insults (diet, toxicants, and stress) in critical periods of developmental plasticity, such as gestation, lactation and adolescence, alter the ECS and may predispose individuals to the development of chronic diseases and behavioral changes in the long term. This review is focused on the ECS and the developmental origins of health and disease (DOHaD).

A manless adultery: the story of Bassa as related in a Marcus Valerius Martialis' epigram

During the Golden Age of the Roman Empire, Rome was transformed into a magnificent city where architecture, the arts, and commerce flourished. An inconceivable amount of wealth was accumulated by a handful of noble families, while the masses starved. In such a context, moral values inevitably decline, while sexual mores are liberalized and ever more veer towards salacity. This reality was elegantly illustrated in short, often sarcastic poems known as epigrams. Herein, we present a case of a woman with enigmatic appearance of the external genitalia, exhibiting unrestrained homosexual activity, as described in an epigram by Marcus Valerius Martialis (a contemporary poet who lived in the 1st century AD). Based on the information provided in the ancient text, we formulate a differential diagnosis and deduce that this woman was, in fact, a case of congenital adrenal hyperplasia (CAH). To our knowledge, this is the earliest literary description worldwide of a case of CAH as a cause of homosexuality and unquenchable lust.

Sex-typical behavior in children born preterm at very low birth weight

BACKGROUND

Perinatal events may alter psychosexual development. We aimed to assess whether a preterm birth at very low birth weight (VLBW; <1500 g) or antenatal synthetic glucocorticoids (sGC) given to the mother are associated with altered sex-typical behavior in childhood.

METHODS

Sex-typical behavior was assessed using the Pre-school Activities Inventory (PSAI) at the mean age of 4.9 years (SD 1.6) in 879 children, of whom 143 were preterm with VLBW (PT <1500 g, all exposed to sGC), 282 were preterm with birth weight ≥1500 g (PT ≥1500 g, 171 exposed to sGC), and 454 were full term (FT, 166 exposed to sGC).

RESULTS

Antenatal sGC was not associated with PSAI scores in either sex. PT <1500 g boys had less male-typical PSAI scores than other boys, even in multivariate model adjusting for age, maternal age, antenatal sGC, number of brothers and sisters, and motor or cognitive impairment. PT <1500 g girls had less female-typical PSAI scores than other girls in the multivariate model. The effect size was small (d = 0.03) for both sexes.

CONCLUSIONS

Preterm birth with VLBW is associated with reduced sex-typical behavior in childhood, which is in line with the previous data indicating altered psychosexual development in adults born preterm. Mechanisms underlying these observations are not fully understood.

IMPACT

Preterm birth is associated with reduced rates of marriage and reproduction in adulthood, but sex-typical behavior in children born preterm has not been studied before. The results of this study indicate that preterm birth with very low birth weight <1500 g is associated with reduced sex-typical behavior in childhood in both sexes. These observations are in line with the previous data indicating altered psychosexual development in adults born preterm. Mechanisms underlying these observations are not fully understood and require further studies.

2D:4D Digit Ratios in Adults with Gender Dysphoria: A Comparison to Their Unaffected Same-Sex Heterosexual Siblings, Cisgender Heterosexual Men, and Cisgender Heterosexual Women

We compared gender dysphoria (GD) patients and their same-sex siblings in terms of their 2D:4D ratios, which may reflect prenatal exposure to androgen, one of the possible etiological mechanisms underlying GD. Sixty-eight GD patients (46 Female-to-Male [FtM]; 22 Male-to-Female [MtF]), 68 siblings (46 sisters of FtMs; 22 brothers of MtFs), and 118 heterosexual controls (62 female; 56 male) were included in the study. FtMs were gynephilic and MtFs were androphilic. We found that 2D:4D ratios in the both right hand (p < .001) and the left hand (p = .003) were lower in male controls than in female controls. Regarding right hands, FtM GD patients had lower 2D:4D ratios than female controls (p < .001) but their ratios did not differ from those of their sisters or male controls. FtM GD patients had no significant difference in their left-hand 2D:4D ratios compared to their sisters or female and male controls. While there was no significant difference in right hands between FtM's sisters and male controls, left-hand 2D:4D ratios were significantly higher in FtM's sisters (p = .017). MtF GD patients had lower right-hand 2D:4D ratios than female controls (p <.001), but their right-hand ratios did not differ from those of their brothers and male controls. There was no significant difference in left-hand 2D:4D ratios between MtF GD patients, and their brothers, or female and male controls. FtM GD patients showed significantly masculinized right-hand 2D:4D ratios, while there was no evidence of feminization in MtF GD patients.

Testosterone and the Brain: From Cognition to Autism

Sex and gender matter in all aspects of life. Humans exhibit sexual dimorphism in anatomy, physiology, but also pathology. Many of the differences are due to sex chromosomes and, thus, genetics, other due to endocrine factors such as sex hormones, some are of social origin. Over the past decades, huge number of scientific studies have revealed striking sex differences of the human brain with remarkable behavioral and cognitive consequences. Prenatal and postnatal testosterone influence brain structures and functions, respectively. Cognitive sex differences include especially certain spatial and language tasks, but they also affect many other aspects of the neurotypical brain. Sex differences of the brain are also relevant for the pathogenesis of neuropsychiatric disorders such as autism spectrum disorders, which are much more prevalent in the male population. Structural dimorphism in the human brain was well-described, but recent controversies now question its importance. On the other hand, solid evidence exists regarding gender differences in several brain functions. This review tries to summarize the current understanding of the complexity of the effects of testosterone on brain with special focus on their role in the known sex differences in healthy individuals and people in the autism spectrum.

Cord blood androgen levels of females from same sex and opposite sex twins - A pilot study

OBJECTIVE

Opposite-sex twins have shown behavioural and reproductive differences between females and males. These differences may be determined by higher intrauterine levels of androgens among females that were exposed to a male co-twin. The aim of this study was to compare cord blood androgen levels in females from same-sex and opposite-sex twins.

DESIGN

A prospective study. In this pilot study, we compared cord blood androgens (DHEA-S, Δ-4 androstenedione, total testosterone-TT) and sex hormone-binding globulin (SHBG) levels in 20 females from same sex and 20 females from opposite-sex dichorionic diamniotic twins. We used generalized estimating equation (GEE) modelling to assess differences in cord blood androgens between females from same-sex twin pregnancies and females from opposite-sex twin pregnancies.

PATIENTS

Twenty opposite-sex twin pairs (female-male twins) and 20 same-sex twin pairs (female-female).

MEASUREMENTS

Cord blood total testosterone, Δ-4 androstenedione, DHEA-S and sex hormone-binding globulin (SHBG) levels.

RESULTS

No difference in the levels of androgens as Δ-4 androstenedione, total testosterone and SHBG was identified between females that were exposed to a female co-twin compared with females that were exposed to a male co-twin. DHEA-S levels were significantly lower among females from opposite-sex twins compared with females from same-sex twins.

CONCLUSIONS

Our preliminary data do not support the hypothesis that females exposed to male co-twins are exposed to higher levels of androgens in utero compared with females exposed to female co-twins. Further studies are needed to explain the reported behavioural and reproductive differences among opposite-sex twins.

Associations between prenatal phthalate exposure and sex-typed play behavior in preschool age boys and girls

Phthalates, a class of chemicals found widely in consumer products including plastic toys, food contaminants and food packaging, personal care products, cosmetics, air fresheners, and some medications, have been shown to be anti-androgenic in numerous laboratory and epidemiological studies. In a prior cohort enrolled in 2000-2002, we observed associations between prenatal urinary concentrations of di-ethyl hexyl phthalate (DEHP) and dibutyl phthalate (DBP) metabolites and less male-typed play behavior in preschool age boys. The aim of this study was to examine phthalate exposure in pregnancy in relation to play behavior at age 4 years in a larger cohort of pregnant women enrolled in The Infant Development and the Environment Study (TIDES) between 2010 and 2012 at four study sites (Minneapolis, MN; Rochester, NY; San Francisco, CA; Seattle, WA). Maternal urinary metabolites of DEHP, DiBP, DnBP, BBzP, and DEP were measured during the first (n=498) and third trimester (n=468) and mothers completed the Preschool Activities Inventory (PSAI), a validated maternal questionnaire designed to assess child toy preference and sex-typed play behavior when children were 4-5 years of age. After adjusting for child age, maternal education, race, urine dilution, parental attitudes about opposite sex-typed play behavior, and presence of a same sex older sibling, we observed associations between first trimester (mean 10.7±2.1 weeks gestation) (log10) SpG-adjusted MnBP, MiBP, and MBzP and lower masculine scores in boys (β-coefficient [95% confidence intervals]: MnBP -2.18, [-4.16, -0.20]), MiBP -2.1[-4.3,0.1], and MBzP -2.42 [-4.12, -0.71]). In girls, first trimester maternal urinary MBzP was associated with lower masculine scores (-2.12 [-3.98,-0.25]), while third trimester (mean 32.8±3.0 weeks gestation) maternal urinary MiBP was associated with higher masculine scores (2.69 [0.68,4.70]). Third trimester maternal urinary phthalate levels were not associated with play behavior in boys. These findings in boys are largely consistent with previous studies that report that prenatal phthalate exposure is associated with less masculine play behavior. No associations in girls have been previously reported.

Autism Spectrum Disorder Genetics and the Search for Pathological Mechanisms

Recent progress in the identification of genes and genomic regions contributing to autism spectrum disorder (ASD) has had a broad impact on our understanding of the nature of genetic risk for a range of psychiatric disorders, on our understanding of ASD biology, and on defining the key challenges now facing the field in efforts to translate gene discovery into an actionable understanding of pathology. While these advances have not yet had a transformative impact on clinical practice, there is nonetheless cause for real optimism: reliable lists of risk genes are large and growing rapidly; the identified encoded proteins have already begun to point to a relatively small number of areas of biology, where parallel advances in neuroscience and functional genomics are yielding profound insights; there is strong evidence pointing to mid-fetal prefrontal cortical development as one nexus of vulnerability for some of the largest-effect ASD risk genes; and there are multiple plausible paths forward toward rational therapeutics development that, while admittedly challenging, constitute fundamental departures from what was possible prior to the era of successful gene discovery.

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

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.

The Effects of Hormonal Contraceptives on the Brain: A Systematic Review of Neuroimaging Studies

Background: Hormonal contraceptive drugs are being used by adult and adolescent women all over the world. Convergent evidence from animal research indicates that contraceptive substances can alter both structure and function of the brain, yet such effects are not part of the public discourse or clinical decision-making concerning these drugs. We thus conducted a systematic review of the neuroimaging literature to assess the current evidence of hormonal contraceptive influence on the human brain.

Methods: The review was registered in PROSPERO and conducted in accordance with the PRISMA criteria for systematic reviews. Structural and functional neuroimaging studies concerning the use of hormonal contraceptives, indexed in Embase, PubMed and/or PsycINFO until February 2020 were included, following a comprehensive and systematic search based on predetermined selection criteria.

Results: A total of 33 articles met the inclusion criteria. Ten of these were structural studies, while 23 were functional investigations. Only one study investigated effects on an adolescent sample. The quality of the articles varied as many had methodological challenges as well as partially unfounded theoretical claims. However, most of the included neuroimaging studies found functional and/or structural brain changes associated with the use of hormonal contraceptives.

Conclusion: The included studies identified structural and functional changes in areas involved in affective and cognitive processing, such as the amygdala, hippocampus, prefrontal cortex and cingulate gyrus. However, only one study reported primary research on a purely adolescent sample. Thus, there is a need for further investigation of the implications of these findings, especially with regard to adolescent girls.

Sexual partner preference in animals and humans

Sex differences in brain and behavior of animals including humans result from an interaction between biological and environmental influences. This is also true for the differences between men and women concerning sexual orientation. Sexual differentiation is mediated by three groups of biological mechanisms: early actions of sex steroids, more direct actions of sex-specific genes not mediated by gonadal sex steroids and epigenetic mechanisms. Differential interactions with parents and conspecifics have additionally long-term influences on behavior. This presentation reviews available evidence indicating that these different mechanisms play a significant role in the control of sexual partner preference in animals and humans, in other words the homosexual versus heterosexual orientation. Clinical and epidemiological studies of phenotypically selected populations indicate that early actions of hormones and genetic factors clearly contribute to the determination of sexual orientation. The maternal embryonic environment also modifies the incidence of male homosexuality via immunological mechanisms. The relative contribution of each of these mechanisms remains however to be determined.

Gender identity, sexual orientation and adverse sexual experiences in autistic females

BACKGROUND

There is growing recognition that autistic females present with more diverse gender and sexual identities than their non-autistic counterparts. Likewise, autistic females are also at an increased risk of adverse sexual experiences. As higher rates of sexual victimisation are observed in individuals with diverse sexual identities in the broader population, rates of negative sexual experiences among autistic females remain unclear. This study aimed to investigate the representation of gender and sexual diversity within autistic females and examine their rates of regretted, and unwanted, sexual encounters among females with a transgender gender identity and non-heterosexual sexual orientation.

METHODS

Two hundred and ninety-five females completed the Sexual Behaviour Scale-III (SBS-III) online. Self-reported gender identity and sexual orientation were compared between 134 autistic (M_age= 26.2 years, SD = 8.7) and 161 non-autistic females (M_age = 22.0 years, SD = 4.6). Differences in the prevalence of negative sexual experiences were compared across diagnosis and each gender identity and sexual orientation label.

RESULTS

Autistic females were more likely to identify with a transgender gender identity (p < .05) and non-heterosexual sexual orientation (p < .007) compared to non-autistic females. Autistic homosexual females were more likely to have experienced a range of negative sexual experiences than autistic heterosexual females (OR ≥ 3.29; p < .01) and were more likely to have experienced unwanted sexual experiences than non-autistic females regardless of sexual orientation (OR ≥ 2.38; p < .05). There were no differences in rates of negative sexual experiences between autistic bisexual and both autistic heterosexual and non-autistic bisexual females. Non-autistic bisexual females (OR = 0.24; p = .018) presented with a reduced risk of regretted sexual experiences than non-autistic heterosexual peers. There were no differences in negative sexual experiences across gender identity in the autistic sample.

LIMITATIONS

The use of fixed format response items may have restricted participants' abilities to provide rich responses pertaining to their sexual identities and nature of negative sexual experiences. The small number of participants who identified as transgender (n = 40) limits the reliability of results pertaining to sexual experiences across gender identity. Moreover, although multiple recruitment methods were used in this study, non-representative may bias estimates of prevalence rates. Thus, the data may not be representative of the broader population.

CONCLUSIONS

Results indicate that autistic females present with greater diversity in their sexual identities than individuals without autism, with those with a homosexual sexual orientation being at greater risk of experiencing adverse sexual encounters. Findings suggest the importance of increased clinical attention to this diversity and the need to provide support to facilitate the development of a healthy sexual identity and reduce the risks identified in this study.

The stability of autistic traits in transgender adults following cross-sex hormone treatment

Background: Recent research has shown that a high percentage of treatment-seeking transgender adults who were assigned female at birth (AFAB) reported scores above the clinical cutoff for autistic traits. It is unclear whether those scores reflect a stable trait or may be inflated by the high levels of anxiety typically associated with transgender people attending clinical services. Aims: This longitudinal study aims to explore the impact of Cross-sex Hormone Treatment (CHT) on levels autistic traits, independent of changes in anxiety. Method: Transgender adults who were assessed at a national transgender health service in the UK, who had not previously received CHT and who had completed the AQ-Short as a measure of autistic traits pre- and one-year post-CHT were included in the study (n = 118). Anxiety was assessed at the same time points using the Hospital Anxiety and Depression Scale. Results: AQ-Short scores remained very stable over time (ICC = 0.7; CIs 0.591-0.779) but anxiety showed little consistency (ICC = 0.386; CIs 0.219 to 0.531). Repeated measures ANOVA found a main effect of assigned sex with AFAB having higher AQ-Short scores. There was no change in AQ-Short scores and no significant interaction between assigned sex and change in AQ-Short scores. Conclusion: This study confirmed that treatment seeking transgender AFAB people have higher levels of autistic traits at follow-up compared to AMAB transgender people and that these traits are stable following one year of CHT regardless of assigned sex. This may have clinical implications regarding the support that transgender people may require following medical transition.

Sexual Orientation in Individuals With Congenital Adrenal Hyperplasia: A Systematic Review

Congenital adrenal hyperplasia (CAH) is a genetic condition of the steroidogenic enzymes in the adrenal cortex normally leading to variable degrees of cortisol and aldosterone deficiency as well as androgen excess. Exposure to androgens prenatally might lead to ambiguous genitalia. The fetal brain develops in traditional male direction through a direct action of androgens on the developing nerve cells, or in the traditional female direction in the absence of androgens. This may indicate that sexual development, including sexual orientation, are programmed into our brain structures prenatally. The objective of this study was to perform a systematic review of the literature, investigating sexual orientation in individuals with CAH. The study also aimed at identifying which measures are used to define sexual orientation across studies. The review is based on articles identified through a comprehensive search of the OVIDMedline, PsycINFO, CINAHL, and Web of Science databases published up to May 2019. All peer-reviewed articles investigating sexual orientation in people with CAH were included. Quantitative, qualitative, and mixed methods were considered, as well as self-, parent-, and third-party reports, and no age or language restrictions were enforced on publications. The present review included 30 studies investigating sexual orientation in patients with CAH assigned female at birth (46, XX) (n = 927) or assigned male at birth (46, XY and 46, XX) (n = 274). Results indicate that assigned females at birth (46, XX) with CAH had a greater likelihood to not have an exclusively heterosexual orientation than females from the general population, whereas no assigned males at birth (46, XY or 46, XX) with CAH identified themselves as non-heterosexual. There was a wide diversity in measures used and a preference for unvalidated and self-constructed interviews. Hence, the results need to be interpreted with caution. Methodological weaknesses might have led to non-heterosexual orientation being overestimated or underestimated. The methodological challenges identified by this review should be further investigated in future studies.

Signatures of sex: Sex differences in gene expression in the vertebrate brain

Women and men differ in disease prevalence, symptoms, and progression rates for many psychiatric and neurological disorders. As more preclinical studies include both sexes in experimental design, an increasing number of sex differences in physiology and behavior have been reported. In the brain, sex-typical behaviors are thought to result from sex-specific patterns of neural activity in response to the same sensory stimulus or context. These differential firing patterns likely arise as a consequence of underlying anatomic or molecular sex differences. Accordingly, gene expression in the brains of females and males has been extensively investigated, with the goal of identifying biological pathways that specify or modulate sex differences in brain function. However, there is surprisingly little consensus on sex-biased genes across studies and only a handful of robust candidates have been pursued in the follow-up experiments. Furthermore, it is not known how or when sex-biased gene expression originates, as few studies have been performed in the developing brain. Here we integrate molecular genetic and neural circuit perspectives to provide a conceptual framework of how sex differences in gene expression can arise in the brain. We detail mechanisms of gene regulation by steroid hormones, highlight landmark studies in rodents and humans, identify emerging themes, and offer recommendations for future research. This article is categorized under: Nervous System Development > Vertebrates: General Principles Gene Expression and Transcriptional Hierarchies > Regulatory Mechanisms Gene Expression and Transcriptional Hierarchies > Sex Determination.

Opposite-sex and same-sex twin studies of physiological, cognitive and behavioral traits

A scientific interest in opposite-sex (OS) twins comes from animal studies showing hormone transfer between fetuses in utero. A parallel effect in humans may occur, especially for OS females who may be exposed to androgens, in particular testosterone, from the male co-twin. Conversely, OS males may be exposed to lower levels of prenatal testosterone than do same-sex (SS) males. In this special issue, we reviewed published studies investigating potential differences between OS and SS twins in physiological, cognitive and behavioral traits focusing on the Twin Testosterone Transfer (TTT) hypothesis. Sixty articles fulfilled the eligibility criteria including 23 studies published since the review by Tapp et al. (2011). In general, studies of cognition are conflicting, but it is the phenotype for which most support for the TTT hypothesis is found. Less consistent evidence has been found regarding physiological and behavioral traits. We hope that this special issue will stimulate a discussion about how an investigation of the TTT hypothesis should continue in future research.

Sex Differences in the Epigenome: A Cause or Consequence of Sexual Differentiation of the Brain?

Females and males display differences in neural activity patterns, behavioral responses, and incidence of psychiatric and neurological diseases. Sex differences in the brain appear throughout the animal kingdom and are largely a consequence of the physiological requirements necessary for the distinct roles of the two sexes in reproduction. As with the rest of the body, gonadal steroid hormones act to specify and regulate many of these differences. It is thought that transient hormonal signaling during brain development gives rise to persistent sex differences in gene expression via an epigenetic mechanism, leading to divergent neurodevelopmental trajectories that may underlie sex differences in disease susceptibility. However, few genes with a persistent sex difference in expression have been identified, and only a handful of studies have employed genome-wide approaches to assess sex differences in epigenomic modifications. To date, there are no confirmed examples of gene regulatory elements that direct sex differences in gene expression in the brain. Here, we review foundational studies in this field, describe transcriptional mechanisms that could act downstream of hormone receptors in the brain, and suggest future approaches for identification and validation of sex-typical gene programs. We propose that sexual differentiation of the brain involves self-perpetuating transcriptional states that canalize sex-specific development.

Research Review: Gender identity in youth: treatment paradigms and controversies

BACKGROUND

Pediatric gender identity has gained increased attention over the past several years in the popular media, political arena, and medical literature. This article reviews terminology in this evolving field, traditional models of gender identity development and their limitations, epidemiology and natural history of cross-gender identification among children and adolescents, co-occurring conditions and behaviors, research into the biological and psychosocial determinants of cross-gender identification, and research into the options regarding and benefits of clinical approaches to gender incongruent youth.

METHODS

Based on a critical review of the extant literature, both theoretical and empirical, that addresses the issue of pediatric gender identity, the authors synthesized what is presently known and what is in need of further research in order to elucidate the developmental trajectory and clinical needs of gender diverse youth.

RESULTS

The field of pediatric gender identity has evolved substantially over the past several years. New research suggests that cross-gender identification is prevalent (approximately 1% of youth). These youth suffer disproportionately high rates of anxiety, depression, and suicidality. Although research into the etiology of cross-gender identification is limited, emerging data have shown that affirmative treatment protocols may improve the high rates of mental health difficulties seen among these patients.

CONCLUSIONS

The field of pediatric gender identity has evolved dramatically. Emerging data suggest that these patients' high rates of anxiety, depression, and suicidality appear to be improved with affirmative protocols, although future longitudinal data are needed.

Psychological adjustment, quality of life, and self-perceptions of reproductive health in males with congenital adrenal hyperplasia: a systematic review

PURPOSE

Congenital adrenal hyperplasia (CAH) has been shown to potentially affect psychological adjustment. However, most research has focused on females, and knowledge about psychological challenges in males remains sparse. The aim of this systematic review was therefore to assess these in males with CAH.

METHODS

We systematically searched the OVID Medline, PsycINFO, CINAHL, and Web of Science databases, for articles published up to April 20, 2018, investigating psychological adjustment in males with CAH.

RESULTS

Eleven studies were included in the review. Three main health domains were identified: psychological and psychiatric health, quality of life (QoL), and self-perceptions of reproductive health. Some studies covered more than one health domain. Seven studies explored psychological adjustment and/or the presence of psychiatric symptoms or disorders. Results indicated that males with CAH had more problems related to internalizing behaviors (negative behaviors directed toward the self) and more negative emotionality compared to reference groups. Six studies examined QoL, five of them reporting reduced QoL compared to reference groups. Three studies explored the impact of fertility and sexual health issues on psychological health with varying results from impaired to normal sexual well-being.

CONCLUSIONS

CAH seems to have an impact on males' psychological health. However, the number of identified studies was limited, included few participants, and revealed divergent findings, demonstrating the need for larger studies and highlighting a number of methodological challenges that should be addressed by future research.

Developmental programming of the female neuroendocrine system by steroids

Developmental programming refers to processes that occur during early life that may have long-term consequences, modulating adult health and disease. Complex diseases, such as diabetes, cancer and cardiovascular disease, have a high prevalence in different populations, are multifactorial, and may have a strong environmental component. The environment interacts with organisms, affecting their behaviour, morphology and physiology. This interaction may induce permanent or long-term changes, and organisms may be more susceptible to environmental factors during certain developmental stages, such as the prenatal and early postnatal periods. Several factors have been identified as responsible for inducing the reprogramming of various reproductive and nonreproductive tissues. Among them, both natural and synthetic steroids, such as endocrine disruptors, are known to have either detrimental or positive effects on organisms depending on the dose of exposure, stage of development and biological sexual background. The present review focuses on the action of steroids and endocrine disruptors as agents involved in developmental programming and on their modulation and effects on female neuroendocrine functions.

Personality and Sexual Orientation: Extension to Asexuality and the HEXACO Model

Previous research has examined self-identified sexual orientation in relation to self-reports on the Big Five personality factors. Here we extend this research by including asexuality as a fourth sexual orientation and by assessing the HEXACO personality factors, using self-report data from a large anonymous online sample (N ≈ 100,000). A large overlap was observed among all sexual orientation groups on all six HEXACO dimensions, but notable group differences also emerged. All nonheterosexual groups, particularly bisexual people, averaged higher in openness to experience than did heterosexuals. Heterosexual men averaged much lower in emotionality than heterosexual women, but only a small difference was observed between gay men and lesbians on this dimension. Asexual men and women averaged lower in extraversion and in some facets of emotionality (specifically, dependence and sentimentality) than did the other sexual orientation groups of the same sex. Results are discussed in relation to the different social realities that each sexual orientation group often experiences, along with the (gender-related) developmental influences hypothesized to underlie in part the origins of sexual orientation.

The Neuroendocrinology of the Microbiota-Gut-Brain Axis: A Behavioural Perspective

The human gut harbours trillions of symbiotic bacteria that play a key role in programming different aspects of host physiology in health and disease. These intestinal microbes are also key components of the gut-brain axis, the bidirectional communication pathway between the gut and the central nervous system (CNS). In addition, the CNS is closely interconnected with the endocrine system to regulate many physiological processes. An expanding body of evidence is supporting the notion that gut microbiota modifications and/or manipulations may also play a crucial role in the manifestation of specific behavioural responses regulated by neuroendocrine pathways. In this review, we will focus on how the intestinal microorganisms interact with elements of the host neuroendocrine system to modify behaviours relevant to stress, eating behaviour, sexual behaviour, social behaviour, cognition and addiction.

Circulating Testosterone as the Hormonal Basis of Sex Differences in Athletic Performance

Elite athletic competitions have separate male and female events due to men's physical advantages in strength, speed, and endurance so that a protected female category with objective entry criteria is required. Prior to puberty, there is no sex difference in circulating testosterone concentrations or athletic performance, but from puberty onward a clear sex difference in athletic performance emerges as circulating testosterone concentrations rise in men because testes produce 30 times more testosterone than before puberty with circulating testosterone exceeding 15-fold that of women at any age. There is a wide sex difference in circulating testosterone concentrations and a reproducible dose-response relationship between circulating testosterone and muscle mass and strength as well as circulating hemoglobin in both men and women. These dichotomies largely account for the sex differences in muscle mass and strength and circulating hemoglobin levels that result in at least an 8% to 12% ergogenic advantage in men. Suppression of elevated circulating testosterone of hyperandrogenic athletes results in negative effects on performance, which are reversed when suppression ceases. Based on the nonoverlapping, bimodal distribution of circulating testosterone concentration (measured by liquid chromatography-mass spectrometry)-and making an allowance for women with mild hyperandrogenism, notably women with polycystic ovary syndrome (who are overrepresented in elite athletics)-the appropriate eligibility criterion for female athletic events should be a circulating testosterone of <5.0 nmol/L. This would include all women other than those with untreated hyperandrogenic disorders of sexual development and noncompliant male-to-female transgender as well as testosterone-treated female-to-male transgender or androgen dopers.

Prenatal testosterone does not explain sex differences in spatial ability

The most consistent sex differences in cognition are found for spatial ability, in which males, on average, outperform females. Utilizing a twin design, two studies have shown that females with male co-twins perform better than females with female co-twins on a mental rotation task. According to the Twin Testosterone Transfer hypothesis (TTT) this advantage is due to in-uterine transmission of testosterone from males to females. The present study tested the TTT across 14 different spatial ability measures, including mental rotation tasks, in a large sample of 19–21-year-old twins. Males performed significantly better than females on all spatial tasks, with effect sizes ranging from η² = 0.02 to η² = 0.16. Females with a male co-twin outperformed females with a female co-twin in two of the tasks. The effect sizes for both differences were negligible (η² < 0.02). Contrary to the previous studies, our results gave no indication that prenatally transferred testosterone, from a male to a female twin, influences sex differences in spatial ability.

Global sex selection techniques for family planning: a narrative review

OBJECTIVE

To document the varying methods of sex selection, both primitive (traditional) as well as advanced forms available around the world.

CONTEXT

With the increasing desire of couples to choose the gender of their offspring, scientific sex-selection methods and techniques have evolved over time; unfortunately, the medical and social consequences have remained poorly emphasised.

METHODS

We searched electronic search engines and grey literature that included research articles from journals, books, websites and news articles in English until August 2016. We comprehensively compiled the findings such as underlying principles, time of use in relation to conception and others.

RESULTS

We classified the techniques into natural methods that rely on physiological conditions and artificial methods, including manipulation of seminal fluid for sex selection. Natural methods include Shettles technique, Whelan Method, Billings Ovulation Method, pre-conception diet, and gender selection kits such as GenSelect and Smart Stork, which rely on timing of intercourse, the vaginal environment, a selective diet and nutraceuticals. More advanced and artificial methods include sperm sorting or Ericsson's method, Microsort, Preimplantation Genetic Diagnosis and Urobiologics PreGender test. The markets for these techniques are prevalent in India where the birth of a son is desired. There is also widespread use of indigenous medicines for sex selection. The review reports side effects such as vaginal infections, hyperstimulation syndrome, multiple pregnancies, birth defects and stillbirths.

CONCLUSION

We conclude that sex-selection practices need urgent intervention in view of the social harm, unwarranted gender bias, and diversion of resources from genuine medical need.

Gene regulatory mechanisms underlying sex differences in brain development and psychiatric disease

The sexual differentiation of the mammalian nervous system requires the precise coordination of the temporal and spatial regulation of gene expression in diverse cell types. Sex hormones act at multiple developmental time points to specify sex-typical differentiation during embryonic and early development and to coordinate subsequent responses to gonadal hormones later in life by establishing sex-typical patterns of epigenetic modifications across the genome. Thus, mutations associated with neuropsychiatric conditions may result in sexually dimorphic symptoms by acting on different neural substrates or chromatin landscapes in males and females. Finally, as stress hormone signaling may directly alter the molecular machinery that interacts with sex hormone receptors to regulate gene expression, the contribution of chronic stress to the pathogenesis or presentation of mental illness may be additionally different between the sexes. Here, we review the mechanisms that contribute to sexual differentiation in the mammalian nervous system and consider some of the implications of these processes for sex differences in neuropsychiatric conditions.

Sexual Orientation in Autism Spectrum Disorder

Clinical impressions suggest a different sexual profile between individuals with and without Autism Spectrum Disorder (ASD). Little is presently known about the demographics of sexual orientation in ASD. Sexual Orientation was surveyed using the Sell Scale of Sexual Orientation in an international online sample of individuals with ASD (N = 309, M = 90, F= 219), aged (M = 32.30 years, SD = 11.93) and this was compared to sexual orientation of typically-developing individuals (N = 310, M = 84, F= 226), aged (M = 29.82 years, SD = 11.85). Findings suggested that sexual orientation was contingent on diagnosis (N = 570, χ²₍₉₎ =104.05, P < 0.001, φ = 0.43). In the group with ASD, 69.7% of the sample reported being non-heterosexual, while in the TD group, 30.3% reported being non-heterosexual. The group with ASD reported higher rates of homosexuality, bisexuality and asexuality, but lower rates of heterosexuality. The results support the impression that non-heterosexuality is more prevalent in the autistic population. Increased non-heterosexuality in ASD has important clinical implications to target unique concerns of this population, and suggests a need for specialized sex education programs for autistic populations for increased support and awareness. Autism Res 2018, 11: 133-141. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

Research suggests that individuals with Autism Spectrum Disorder (ASD) report increased homosexuality, bisexuality, and asexuality, but decreased heterosexuality. It is important to increase awareness about increased non-heterosexuality in ASD among autistic populations, medical professionals and care-takers, so as to provide specialized care, if needed and increase support and inclusion for non-heterosexual autistic individuals.

No effect of testosterone on behavior in aged Wistar rats

In men, aging is accompanied by a gradual decline in androgen secretion. Studies suggest beneficial effects of endogenous and exogenous testosterone on affective behavior and cognitive functions. The aim of this study was to describe behavioral and cognitive sex differences and to analyze the effects of long-term androgen deficiency in aged male rats. Thirty-months old rats divided into three groups (males, females and males gonadectomized as young adults) underwent a battery of behavioral tests assessing locomotor activity, anxiety, memory, anhedonia, sociability and depression-like behavior. No major effect of gonadectomy was found in any of the analyzed behavioral measures in male rats. The only consistent sex difference was confirmed in depression-like behavior with longer immobility time observed in males. In an interventional experiment, a single dose of testosterone had no effect on gonadectomized male and female rats in the forced swim test. In contrast to previous studies this comprehensive behavioral phenotyping of aged rats revealed no major role of endogenous testosterone. Based on our results long-term hypogonadism does not alter the behavior of aged male rats, neither does acute testosterone treatment. Whether these findings have any consequences on androgen replacement therapy in aged men remains to be elucidated.

Controversies of Sex Re-assignment in Genetic Males with Congenital Inadequacy of the Penis

Sex assignment in 46XY genetic male children with congenital inadequacy of the penis (CIP) is controversial. Traditionally, children with penile length less than 2 cm at birth are considered unsuitable to be raised as males. They are typically re-assigned to female-sex and feminizing genitoplasty is usually done in infancy. However, the concept of cerebral androgen imprinting has caused paradigm shift in the philosophy of sex re-assignment. Masculinization of the brain, rather than length of the penis, is the modern criterion of sex re-assignment in CIP. This review summarizes the current understanding of the complex issue. In 46XY children with CIP, male-sex assignment appears appropriate in non-hormonal conditions such as idiopathic micropenis, aphallia and exstrophy. Female-sex re-assignment appears acceptable in complete androgen insensitivity (CAIS), while partial androgen insensitivity syndrome (PAIS) patients are highly dissatisfied with the assignment of either sex. Children with 5-alpha reductase deficiency are likely to have spontaneous penile lengthening at puberty. Hence, they are better raised as males. Although female assignment is common in pure gonadal dysgenesis, long-term results are not known to justify the decision.

Yolk testosterone affects growth and promotes individual-level consistency in behavioral lateralization of yellow-legged gull chicks

Behavioral lateralization is common in animals and may be expressed at the individual- and at the population-level. The ontogenetic processes that control lateralization, however, are largely unknown. Well-established sex-dependence in androgen physiology and sex-dependent variation in lateralization have led to the hypothesis that testosterone (T) has organizational effects on lateralization. The effects of T exposure in early life on lateralization can be efficiently investigated by manipulating T levels in the cleidoic eggs of birds, because the embryo is isolated from maternal and sibling physiological interference, but this approach has been adopted very rarely. In the yellow-legged gull (Larus michahellis) we increased yolk T concentration within the physiological limits and tested the effects on the direction of lateralization in two functionally fundamental behaviors (begging for parental care and escape to cover) of molecularly sexed hatchlings. We also speculated that T may intervene in regulating consistency, rather than direction of lateralization, and therefore tested if T affected the 'repeatability' of lateral preference in consecutive behavioral trials. T treatment had no effect on the direction of lateralization, but enhanced the consistency of lateral preference in escape responses. Sex did not predict lateralization. Neither behavior was lateralized at the population-level. We therefore showed for the first time in any species an effect of egg T on consistency in lateralization. The implications of the effect of T for the evolution of trade-offs in maternal allocation of egg hormones, and the evolutionary interpretations of findings from our studies on lateralization among unmanipulated birds are discussed.

Personality and gender differences in global perspective

Men's and women's personalities appear to differ in several respects. Social role theories of development assume gender differences result primarily from perceived gender roles, gender socialization and sociostructural power differentials. As a consequence, social role theorists expect gender differences in personality to be smaller in cultures with more gender egalitarianism. Several large cross-cultural studies have generated sufficient data for evaluating these global personality predictions. Empirically, evidence suggests gender differences in most aspects of personality-Big Five traits, Dark Triad traits, self-esteem, subjective well-being, depression and values-are conspicuously larger in cultures with more egalitarian gender roles, gender socialization and sociopolitical gender equity. Similar patterns are evident when examining objectively measured attributes such as tested cognitive abilities and physical traits such as height and blood pressure. Social role theory appears inadequate for explaining some of the observed cultural variations in men's and women's personalities. Evolutionary theories regarding ecologically-evoked gender differences are described that may prove more useful in explaining global variation in human personality.

Social communication and emotion difficulties and second to fourth digit ratio in a large community-based sample

Background

Recent research investigating the extreme male brain theory of autism spectrum disorders (ASD) has drawn attention to the possibility that autistic type social difficulties may be associated with high prenatal testosterone exposure. This study aims to investigate the association between social communication and emotion recognition difficulties and second to fourth digit ratio (2D:4D) and circulating maternal testosterone during pregnancy in a large community-based cohort: the Avon Longitudinal Study of Parents and Children (ALSPAC). A secondary aim is to investigate possible gender differences in the associations.

Methods

Data on social communication (Social and Communication Disorders Checklist, N = 7165), emotion recognition (emotional triangles, N = 5844 and diagnostics analysis of non-verbal accuracy, N = 7488) and 2D:4D (second to fourth digit ratio, N = 7159) were collected in childhood and early adolescence from questionnaires and face-to-face assessments. Complete data was available on 3515 children. Maternal circulating testosterone during pregnancy was available in a subsample of 89 children.

Results

Males had lower 2D:4D ratios than females [t (3513) = −9.775, p < 0.001]. An association was found between measures of social communication and emotion recognition, and the lowest 10 % of 2D:4D ratios. A significant association was found between maternal circulating testosterone and left hand 2D:4D [OR = 1.65, 95 % CI 1.1–2.4, p < 0.01].

Conclusions

Previous findings on the association between 2D:4D and social communication difficulties were not confirmed. A novel association between an extreme measure of 2D:4D in males suggests threshold effects and warrants replication.

Electronic supplementary material

The online version of this article (doi:10.1186/s13229-015-0063-7) contains supplementary material, which is available to authorized users.

Consumption of indigenous medicines by pregnant women in North India for selecting sex of the foetus: what can it lead to?

BACKGROUND

Sex ratio is an important indicator of development. Despite all the measures undertaken for improvement, it remains an issue of concern in India, with Haryana having a very low sex ratio in the country. Studies have been conducted indicating that consumption of indigenous drugs used for sex selection (SSD) could be strongly associated with adverse effects on the foetal development, including congenital malformations. Some samples of SSDs were collected from parts of North India and analysed in a standard laboratory for its components.

METHODS

Thirty SSDs used by the local community were procured from various sources in north India through a rigorous process of collection. These were subjected to laboratory tests to investigate the presence of phytoestrogen and testosterone. Following sample extraction, thin layer chromatography and high performance liquid chromatography were carried out for analysing phytoestrogen content.

RESULTS

SSDs were available in various forms such as powder, tablets, mostly from faith healers. Around 87% of the samples collected from sources like doctors, quacks and faith healers were to be taken by the pregnant women after conception; 63% drugs were strongly positive for phytoestrogens (genistein, daidzein, formononetin) and 20% drugs were positive for testosterone. The average dose of the components as calculated after analyses was as follows: daidzein--14.1 mg/g sample, genistein--8.6 mg/g sample, formononetin--5 mg/g sample.

CONCLUSION

These SSDs could be potentially detrimental to the growth and development of the foetus. This is likely to have implications on the health of the community. In view of the results obtained in our study, we strongly attest the importance in curbing this harmful practice by banning the supply of the drugs as well as by advocating behavioural changes in the community.

Gender Role, Gender Identity and Sexual Orientation in CAIS ("XY-Women") Compared With Subfertile and Infertile 46,XX Women

The perception of gender development of individuals with complete androgen insensitivity syndrome (CAIS) as unambiguously female has recently been challenged in both qualitative data and case reports of male gender identity. The aim of the mixed-method study presented was to examine the self-perception of CAIS individuals regarding different aspects of gender and to identify commonalities and differences in comparison with subfertile and infertile XX-chromosomal women with diagnoses of Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) and polycystic ovary syndrome (PCOS). The study sample comprised 11 participants with CAIS, 49 with MRKHS, and 55 with PCOS. Gender identity was assessed by means of a multidimensional instrument, which showed significant differences between the CAIS group and the XX-chromosomal women. Other-than-female gender roles and neither-female-nor-male sexes/genders were reported only by individuals with CAIS. The percentage with a not exclusively androphile sexual orientation was unexceptionally high in the CAIS group compared to the prevalence in "normative" women and the clinical groups. The findings support the assumption made by Meyer-Bahlburg ( 2010 ) that gender outcome in people with CAIS is more variable than generally stated. Parents and professionals should thus be open to courses of gender development other than typically female in individuals with CAIS.

The perinatal androgen to estrogen ratio and autistic-like traits in the general population: a longitudinal pregnancy cohort study

BACKGROUND

Prenatal androgen exposure has been hypothesized to be linked to autism spectrum disorder (ASD). While previous studies have found a link between testosterone levels in amniotic fluid and autistic-like traits, a similar relationship has not been found for testosterone in umbilical cord blood. However, it may be the net biological activity of multiple androgens and estrogens that influences postnatal effects of prenatal sex steroids. Accordingly, composite levels of androgens (A) and estrogens (E) were investigated, along with their ratio, in relation to autistic-like traits in young adulthood.

METHODS

Sex steroid data in umbilical cord blood were available from 860 individuals at delivery. Samples were analyzed for androgens (testosterone, androstenedione, and dehydroepiandrosterone) and estrogens (estrone, estradiol, estriol, and estetrol). Levels of bioavailable testosterone, estradiol, and estrone were measured and used to calculate A and E composites and the A to E ratio. Participants were approached in early adulthood to complete the autism-spectrum quotient (AQ) as a self-report measure of autistic-like traits, with 183 males (M = 20.10 years, SD = 0.65 years) and 189 females (M =19.92 years, SD = 0.68 years) providing data.

RESULTS

Males exhibited significantly higher androgen composites and A to E composite ratios than females. Males also scored significantly higher on the details/patterns subscale of the AQ. Subsequent categorical and continuous analyses, which accounted for covariates, revealed no substantial relationships between the A/E composites or the A to E ratio and the AQ total or subscale scores.

CONCLUSIONS

The current study found no link between the A/E composites or the A to E ratio in cord blood and autistic-like traits in the population as measured by the AQ. These outcomes do not exclude the possibility that these sex steroid variables may predict other neurodevelopmental traits in early development.