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VanderLaan DP, Skorska MN, Peragine DE, Coome LA. Carving the Biodevelopment of Same-Sex Sexual Orientation at Its Joints. ARCHIVES OF SEXUAL BEHAVIOR 2023; 52:2939-2962. [PMID: 35960401 DOI: 10.1007/s10508-022-02360-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/30/2022] [Accepted: 06/04/2022] [Indexed: 06/15/2023]
Abstract
Sexual orientation is a core aspect of human experience and understanding its development is fundamental to psychology as a scientific discipline. Biological perspectives have played an important role in uncovering the processes that contribute to sexual orientation development. Research in this field has relied on a variety of populations, including community, clinical, and cross-cultural samples, and has commonly focused on female gynephilia (i.e., female sexual attraction to adult females) and male androphilia (i.e., male sexual attraction to adult males). Genetic, hormonal, and immunological processes all appear to influence sexual orientation. Consistent with biological perspectives, there are sexual orientation differences in brain development and evidence indicates that similar biological influences apply across cultures. An outstanding question in the field is whether the hypothesized biological influences are all part of the same process or represent different developmental pathways leading to same-sex sexual orientation. Some studies indicate that same-sex sexually oriented people can be divided into subgroups who likely experienced different biological influences. Consideration of gender expression in addition to sexual orientation might help delineate such subgroups. Thus, future research on the possible existence of such subgroups could prove to be valuable for uncovering the biological development of sexual orientation. Recommendations for such future research are discussed.
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Affiliation(s)
- Doug P VanderLaan
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada.
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada.
| | - Malvina N Skorska
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Diana E Peragine
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
| | - Lindsay A Coome
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
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2
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Blanchard R, Lippa RA. Reassessing the Effect of Older Sisters on Sexual Orientation in Men. ARCHIVES OF SEXUAL BEHAVIOR 2021; 50:797-805. [PMID: 33025292 DOI: 10.1007/s10508-020-01840-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
This research reanalyzed questionnaire data from 8279 homosexual and 79,519 heterosexual men who participated in 2005 in an internet-based research project sponsored by the British Broadcasting Corporation. It focused on parameters of sibship composition (older brothers, older sisters, younger siblings) previously shown or hypothesized to influence sexual orientation in males. The results included the usual finding that older brothers increase the odds of homosexuality in later-born males. As predicted, older sisters also increase those odds, although by a lesser amount than older brothers. Other results confirmed that the odds of homosexuality are increased in only-children, the amount of increase being equal to that produced by one older brother and greater than that produced by one older sister. Finally, the results indicated that younger siblings have no effect on the odds of homosexuality in males. These results might be explained by the hypothesis that two different types of immune responses in pregnant women can affect the future sexual orientation of their male fetuses. One type of response affects fetuses in first pregnancies and reduces subsequent fertility. The other type affects fetuses in later pregnancies and has little or no effect on fertility. Finally, we conducted an estimate of combined sibship effects. Men who were exposed to any of the influences that we identified (being an only-child or having an older sibling) had 27% greater odds of homosexuality than did subjects who were exposed to none of these influences (i.e., the first-born of two or more children).
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Affiliation(s)
- Ray Blanchard
- Department of Psychiatry, University of Toronto, Toronto, ON, M5T 1R8, Canada.
| | - Richard A Lippa
- Department of Psychology, California State University, Fullerton, CA, USA
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Skorska MN, Coome LA, Saokhieo P, Kaewthip O, Chariyalertsak S, VanderLaan DP. Handedness and Birth Order Among Heterosexual Men, Gay Men, and Sao Praphet Song in Northern Thailand. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:2431-2448. [PMID: 32623540 DOI: 10.1007/s10508-020-01774-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
Previous research has examined handedness and birth order to inform sexual orientation and gender identity/role expression development; however, sexual orientation and gender identity/role expression have rarely been disentangled to provide a more nuanced perspective. In Thailand, we investigated sexual orientation and gender identity simultaneously via comparison of 282 heterosexual men, 201 gay men, and 178 sao praphet song-i.e., androphilic, markedly feminine males recognized as a "third" gender. Handedness was examined as: extremely left-handed, moderately left-handed, ambidextrous, moderately right-handed, or extremely right-handed. Birth order was examined as numbers of older and younger brothers and sisters, by using Berglin's, fraternal, and sororal indices, and by examining the older brother odds ratio and sibling sex ratio. Compared with heterosexual men, gay men and sao praphet song were more likely to be extremely right-handed. Sao praphet song were also more likely to be extremely left-handed than heterosexual and gay men. Heterosexual men and sao praphet song had later sororal birth order compared with the expected Thai population value, suggesting stopping rules influenced when probands' mothers ceased having children. These findings provide new insights and replicate previous findings in a non-Western sample. Regarding handedness, in males, mechanisms related to extreme right-handedness likely influence the development of androphilia, whereas mechanisms related to both extreme right- and extreme left-handedness likely explain the combination of androphilia and feminine gender identity/role expression. Regarding birth order, similar to the conclusions of some prior research, stopping rules pose a challenge for testing the fraternal birth order effect.
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Affiliation(s)
- Malvina N Skorska
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada
| | - Lindsay A Coome
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada
| | - Pongpun Saokhieo
- Research Institute of Health Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Oranitcha Kaewthip
- Research Institute of Health Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Suwat Chariyalertsak
- Research Institute of Health Sciences, Chiang Mai University, Chiang Mai, Thailand
- Faculty of Public Health, Chiang Mai University, Chiang Mai, Thailand
| | - Doug P VanderLaan
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada.
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada.
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Gómez Jiménez FR, Semenyna SW, Vasey PL. Offspring Production Among the Relatives of Istmo Zapotec Men and Muxes. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:581-594. [PMID: 31897830 DOI: 10.1007/s10508-019-01611-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/12/2019] [Accepted: 12/14/2019] [Indexed: 06/10/2023]
Abstract
Male androphilia (i.e., sexual attraction toward adult males) is influenced by biological factors, reliably occurs across diverse cultures, and has persisted over evolutionary time despite the fact that it reduces reproduction. One possible solution to this evolutionary paradox is the sexually antagonistic gene hypothesis (SAGH), which states that genes associated with male androphilia reduce reproduction when present in males but increase reproduction when present in their female relatives. The present study tested the SAGH among the Istmo Zapotec-a non-Euro-American culture in Oaxaca, Mexico, where transgender and cisgender androphilic males are known as muxe gunaa and muxe nguiiu, respectively. To test the SAGH, we compared offspring production by the biological relatives of muxe gunaa (n = 115), muxe nguiiu (n = 112), and gynephilic men (i.e., cisgender males who are sexually attracted to adult females; n = 171). The mothers and paternal aunts of muxe gunaa had higher offspring production than those of muxe nguiiu. Additionally, the relatives of muxe gunaa had more offspring than those of gynephilic men, whereas no such differences were found between the families of gynephilic men and muxe nguiiu. Elevated reproduction by the mothers and, particularly the aunts, of muxe gunaa is consistent with the SAGH. However, the absence of group differences between gynephilic men and muxe nguiiu, and the group differences between the two types of muxes are not predicted by the SAGH. This is the first study to demonstrate reproductive differences between kin of transgender and cisgender androphilic males within the same non-Euro-American culture.
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Affiliation(s)
- Francisco R Gómez Jiménez
- Department of Psychology, University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada.
| | - Scott W Semenyna
- Department of Psychology, University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
| | - Paul L Vasey
- Department of Psychology, University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
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Skorska MN, Bogaert AF. Fraternal Birth Order, Only-Child Status, and Sibling Sex Ratio Related to Sexual Orientation in the Add Health Data: A Re-analysis and Extended Findings. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:557-573. [PMID: 31802291 PMCID: PMC8241527 DOI: 10.1007/s10508-019-01496-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 05/18/2023]
Abstract
The fraternal birth order (FBO) effect related to men's sexual orientation refers to the finding that the number of older brothers that a man has increases his chance of being androphilic. The FBO effect has generally been well replicated in diverse samples; one instance of non-replication was by Francis (2008) using Waves I and III of the Add Health data. We attempted to replicate the FBO effect in the Add Health data taking into account family size and other limitations of Francis' (2008) analyses. Also, we examined other sibling characteristics related to the FBO effect: sibling sex ratio and only-child status. We used two subsamples from Waves I (n = 20,745) and IV (n = 15,701) of the Add Health data, consisting of adolescents who were followed longitudinally from 1994 to 1995 until 2008. Wave I data were used to compute numbers of younger and older brothers and sisters from household roster information. Wave IV information about sexual orientation identity was used. Analyses were conducted within men and within women. We found modest support for the FBO effect in men, but not in women, using the older brother odds ratio, logistic regression analyses, and sibling sex ratio, which provided the strongest support for FBO. We found that gynephilic/biphilic women, but not androphilic/biphilic men, were more likely to be only-children compared to androphilic women and gynephilic men, respectively. We discuss limitations of the Add Health data and purported mechanisms for the FBO effect in men and the only-child effect in women.
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Affiliation(s)
- Malvina N Skorska
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada.
- Department of Psychology, Brock University, St. Catharines, ON, Canada.
| | - Anthony F Bogaert
- Department of Psychology, Brock University, St. Catharines, ON, Canada
- Department of Health Sciences, Brock University, St. Catharines, ON, Canada
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Xu Y, Norton S, Rahman Q. A longitudinal birth cohort study of early life conditions, psychosocial factors, and emerging adolescent sexual orientation. Dev Psychobiol 2019; 62:5-20. [DOI: 10.1002/dev.21894] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/15/2019] [Accepted: 06/22/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Yin Xu
- Department of Psychology, Institute of Psychiatry Psychology and Neuroscience King's College London London UK
| | - Sam Norton
- Department of Psychology, Institute of Psychiatry Psychology and Neuroscience King's College London London UK
| | - Qazi Rahman
- Department of Psychology, Institute of Psychiatry Psychology and Neuroscience King's College London London UK
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Evidence for distinct biodevelopmental influences on male sexual orientation. Proc Natl Acad Sci U S A 2019; 116:12787-12792. [PMID: 31182568 DOI: 10.1073/pnas.1809920116] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Several biological mechanisms have been proposed to influence male sexual orientation, but the extent to which these mechanisms cooccur is unclear. Putative markers of biological processes are often used to evaluate the biological basis of male sexual orientation, including fraternal birth order, handedness, and familiality of same-sex sexual orientation; these biomarkers are proxies for immunological, endocrine, and genetic mechanisms. Here, we used latent profile analysis (LPA) to assess whether these biomarkers cluster within the same individuals or are present in different subgroups of nonheterosexual men. LPA defined four profiles of men based on these biomarkers: 1) A subgroup who did not have these biomarkers, 2) fraternal birth order, 3) handedness, and 4) familiality. While the majority of both heterosexual and nonheterosexual men were grouped in the profile that did not have any biomarker, the three profiles associated with a biomarker were composed primarily of nonheterosexual men. We then evaluated whether these subgroups differed on measures of gender nonconformity and personality that reliably show male sexual orientation differences. The subgroup without biomarkers was the most gender-conforming whereas the fraternal birth order subgroup was the most female-typical and agreeable, compared with the other profiles. Together, these findings suggest there are multiple distinct biodevelopmental pathways influencing same-sex sexual orientation in men.
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Coome LA, Skorska MN, van der Miesen AI, Peragine DE, VanderLaan DP. An examination of the biodevelopment of gender expression in children ages 6- to 12-years. CANADIAN JOURNAL OF HUMAN SEXUALITY 2018. [DOI: 10.3138/cjhs.2018-0013] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Lindsay A. Coome
- Department of Psychology, University of Toronto, Mississauga, ON
| | | | - Anna I.R. van der Miesen
- Center of Expertise on Gender Dysphoria, VU University Medical Center, Amsterdam, The Netherlands
| | | | - Doug P. VanderLaan
- Department of Psychology, University of Toronto, Mississauga, ON
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON
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O'Hanlan KA, Gordon JC, Sullivan MW. Biological origins of sexual orientation and gender identity: Impact on health. Gynecol Oncol 2018; 149:33-42. [PMID: 29605047 DOI: 10.1016/j.ygyno.2017.11.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/30/2017] [Accepted: 11/07/2017] [Indexed: 01/19/2023]
Abstract
Gynecologic Oncologists are sometimes consulted to care for patients who present with diverse gender identities or sexual orientations. Clinicians can create more helpful relationships with their patients if they understand the etiologies of these diverse expressions of sexual humanity. Multidisciplinary evidence reveals that a sexually dimorphic spectrum of somatic and neurologic anatomy, traits and abilities, including sexual orientation and gender identity, are conferred together during the first half of pregnancy due to genetics, epigenetics and the diversity of timing and function of sex chromosomes, sex-determining protein secretion, gonadal hormone secretion, receptor levels, adrenal function, maternally ingested dietary hormones, fetal health, and many other factors. Multiple layers of evidence confirm that sexual orientation and gender identity are as biological, innate and immutable as the other traits conferred during that critical time in gestation. Negative social responses to diverse orientations or gender identities have caused marginalization of these individuals with resultant alienation from medical care, reduced self-care and reduced access to medical care. The increased risks for many diseases, including gynecologic cancers are reviewed. Gynecologic Oncologists can potentially create more effective healthcare relationships with their patients if they have this information.
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Affiliation(s)
- Katherine A O'Hanlan
- Laparoscopic Institute for Gynecology and Oncology (LIGO), 4370 Alpine Rd. Suite 104, Portola Valley, CA 94028, United States.
| | - Jennifer C Gordon
- University of Tennessee Health Sciences Center, Memphis, TN, United States.
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Swift-Gallant A, Coome LA, Monks DA, VanderLaan DP. Gender Nonconformity and Birth Order in Relation to Anal Sex Role Among Gay Men. ARCHIVES OF SEXUAL BEHAVIOR 2018; 47:1041-1052. [PMID: 28378093 DOI: 10.1007/s10508-017-0980-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 03/18/2017] [Accepted: 03/20/2017] [Indexed: 06/07/2023]
Abstract
Androphilia is associated with an elevated number of older brothers among natal males. This association, termed the fraternal birth order effect, has been observed among gay men who exhibit marked gender nonconformity. Gender nonconformity has been linked to gay men's preferred anal sex role. The present study investigated whether these two lines of research intersect by addressing whether the fraternal birth order effect was associated with both gender nonconformity and a receptive anal sex role (243 gay men, 91 heterosexual men). Consistent with previous research, we identified the fraternal birth order effect in our sample of gay men. Also, gay men were significantly more gender-nonconforming on adulthood and recalled childhood measures compared to heterosexual men. When gay men were compared based on anal sex role (i.e., top, versatile, bottom), all groups showed significantly greater recalled childhood and adult male gender nonconformity than heterosexual men, but bottoms were most nonconforming. Only gay men with a bottom anal sex role showed evidence of a fraternal birth order effect. A sororal birth order effect was found in our sample of gay men, driven by versatiles. No significant associations were found between fraternal birth order and gender nonconformity measures. These results suggest that the fraternal birth order effect may apply to a subset of gay men who have a bottom anal sex role preference and that this subgroup is more gender-nonconforming. However, there were no significant associations between fraternal birth order and gender nonconformity at the individual level. As such, based on the present study, whether processes underpinning the fraternal birth order effect influence gender nonconformity is equivocal.
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Affiliation(s)
- Ashlyn Swift-Gallant
- Department of Psychology, University of Toronto, 100 St. George St., Toronto, ON, M5S 3G3, Canada
- Department of Psychology, University of Toronto at Mississauga, 3359 Mississauga Rd. N., Mississauga, ON, L5L 1C6, Canada
| | - Lindsay A Coome
- Department of Psychology, University of Toronto, 100 St. George St., Toronto, ON, M5S 3G3, Canada
- Department of Psychology, University of Toronto at Mississauga, 3359 Mississauga Rd. N., Mississauga, ON, L5L 1C6, Canada
| | - D Ashley Monks
- Department of Psychology, University of Toronto, 100 St. George St., Toronto, ON, M5S 3G3, Canada
- Department of Psychology, University of Toronto at Mississauga, 3359 Mississauga Rd. N., Mississauga, ON, L5L 1C6, Canada
| | - Doug P VanderLaan
- Department of Psychology, University of Toronto, 100 St. George St., Toronto, ON, M5S 3G3, Canada.
- Department of Psychology, University of Toronto at Mississauga, 3359 Mississauga Rd. N., Mississauga, ON, L5L 1C6, Canada.
- Underserved Populations Research Program, Child, Youth and Family Division, Centre for Addiction and Mental Health, 1001 Queen St. W., Toronto, ON, M6J 1H4, Canada.
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Sabuncuoglu O. Commentary on "Gay Male Only-Children: Evidence for Low Birth Weight and High Maternal Miscarriage Rates" from the Prenatal Thyroid Model Perspective. ARCHIVES OF SEXUAL BEHAVIOR 2018; 47:323-325. [PMID: 29204814 DOI: 10.1007/s10508-017-1122-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 11/19/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Osman Sabuncuoglu
- Department of Child and Adolescent Psychiatry, School of Medicine, Marmara University Hospital, Fevzi Cakmak Mah. Muhsin Yazicioglu Cad. No: 10, Pendik, 34899, Istanbul, Turkey.
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Swift-Gallant A, Breedlove SM. O Gay New World: Ramifications of the Maternal Immune Hypothesis. ARCHIVES OF SEXUAL BEHAVIOR 2018; 47:39-41. [PMID: 29188406 DOI: 10.1007/s10508-017-1118-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Ashlyn Swift-Gallant
- Neuroscience Program and Departments of Psychology and Integrative Biology, Michigan State University, 293 Farm Lane, East Lansing, MI, 48824, USA
| | - S Marc Breedlove
- Neuroscience Program and Departments of Psychology and Integrative Biology, Michigan State University, 293 Farm Lane, East Lansing, MI, 48824, USA.
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Abstract
Gay men have, on average, a greater number of older brothers than do heterosexual men, a well-known finding within sexual science. This finding has been termed the fraternal birth order effect. Strong scientific interest in sexual orientation exists because it is a fundamental human characteristic, and because its origins are often the focal point of considerable social controversy. Our study is a major advance in understanding the origins of sexual orientation in men by providing support for a theorized but previously unexamined biological mechanism—a maternal immune response to a protein important in male fetal brain development—and by beginning to explain one of the most reliable correlates of male homosexuality: older brothers. We conducted a direct test of an immunological explanation of the finding that gay men have a greater number of older brothers than do heterosexual men. This explanation posits that some mothers develop antibodies against a Y-linked protein important in male brain development, and that this effect becomes increasingly likely with each male gestation, altering brain structures underlying sexual orientation in their later-born sons. Immune assays targeting two Y-linked proteins important in brain development—protocadherin 11 Y-linked (PCDH11Y) and neuroligin 4 Y-linked (NLGN4Y; isoforms 1 and 2)—were developed. Plasma from mothers of sons, about half of whom had a gay son, along with additional controls (women with no sons, men) was analyzed for male protein-specific antibodies. Results indicated women had significantly higher anti-NLGN4Y levels than men. In addition, after statistically controlling for number of pregnancies, mothers of gay sons, particularly those with older brothers, had significantly higher anti-NLGN4Y levels than did the control samples of women, including mothers of heterosexual sons. The results suggest an association between a maternal immune response to NLGN4Y and subsequent sexual orientation in male offspring.
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Sabuncuoglu O. Towards a further understanding of prenatal thyroid theory of homosexuality: Autoimmune thyroiditis, polycystic ovary syndrome, autism and low birth weight. Ment Illn 2017; 9:7325. [PMID: 29142667 PMCID: PMC5661141 DOI: 10.4081/mi.2017.7325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/12/2017] [Accepted: 09/15/2017] [Indexed: 12/23/2022] Open
Abstract
Research into the neurobiological origins of same-sex attraction is inconclusive. A recent theory of homosexuality posited that maternal thyroid dysfunction during pregnancy is associated with an increased rate of homosexual orientation in offspring. Relevant studies from the prenatal thyroid model perspective were reviewed, the major findings of which are as follows: i) An increased prevalence of Hashimoto’s disease in lesbian women suggests a maternal and even familial presence of the same autoimmune thyroid disease. Female-tomale transsexuals and lesbian women were also reported to have higher rates of polycystic ovary syndrome (PCOS). Over the last several years, reports suggesting a strong link between PCOS and thyroid autoimmunity have accumulated. ii) The increased risk of autism spectrum disorders (ASD) in the offspring of mothers with thyroid autoimmunity in pregnancy and the association between ASD and gender dysphoria indicate a link between maternal thyroid dysfunction and gender dysphoria/same-sex attraction in the offspring. iii) The high risk of miscarriage and retarded fetal growth in pregnancies of mothers who give birth to homosexual offspring can be explained by the impact of maternal thyroid dysfunction during pregnancy. This perspective review highlights relevant research findings and integrates them into the prenatal thyroid model of homosexuality. A better understanding of the mechanisms involved in the generation of same-sex orientation will contribute to the betterment of individual lives, as well as of society.
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Affiliation(s)
- Osman Sabuncuoglu
- Department of Child and Adolescent Psychiatry, School of Medicine, Marmara University Hospital, Istanbul, Turkey
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