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Structural connections in the brain in relation to gender identity and sexual orientation

Both transgenderism and homosexuality are facets of human biology, believed to derive from different sexual differentiation of the brain. The two phenomena are, however, fundamentally unalike, despite an increased prevalence of homosexuality among transgender populations. Transgenderism is associate...

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Autores principales: Burke, Sarah M., Manzouri, Amir H., Savic, Ivanka
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5738422/
https://www.ncbi.nlm.nih.gov/pubmed/29263327
http://dx.doi.org/10.1038/s41598-017-17352-8
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author Burke, Sarah M.
Manzouri, Amir H.
Savic, Ivanka
author_facet Burke, Sarah M.
Manzouri, Amir H.
Savic, Ivanka
author_sort Burke, Sarah M.
collection PubMed
description Both transgenderism and homosexuality are facets of human biology, believed to derive from different sexual differentiation of the brain. The two phenomena are, however, fundamentally unalike, despite an increased prevalence of homosexuality among transgender populations. Transgenderism is associated with strong feelings of incongruence between one’s physical sex and experienced gender, not reported in homosexual persons. The present study searches to find neural correlates for the respective conditions, using fractional anisotropy (FA) as a measure of white matter connections that has consistently shown sex differences. We compared FA in 40 transgender men (female birth-assigned sex) and 27 transgender women (male birth-assigned sex), with both homosexual (29 male, 30 female) and heterosexual (40 male, 40 female) cisgender controls. Previously reported sex differences in FA were reproduced in cis-heterosexual groups, but were not found among the cis-homosexual groups. After controlling for sexual orientation, the transgender groups showed sex-typical FA-values. The only exception was the right inferior fronto-occipital tract, connecting parietal and frontal brain areas that mediate own body perception. Our findings suggest that the neuroanatomical signature of transgenderism is related to brain areas processing the perception of self and body ownership, whereas homosexuality seems to be associated with less cerebral sexual differentiation.
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spelling pubmed-57384222017-12-22 Structural connections in the brain in relation to gender identity and sexual orientation Burke, Sarah M. Manzouri, Amir H. Savic, Ivanka Sci Rep Article Both transgenderism and homosexuality are facets of human biology, believed to derive from different sexual differentiation of the brain. The two phenomena are, however, fundamentally unalike, despite an increased prevalence of homosexuality among transgender populations. Transgenderism is associated with strong feelings of incongruence between one’s physical sex and experienced gender, not reported in homosexual persons. The present study searches to find neural correlates for the respective conditions, using fractional anisotropy (FA) as a measure of white matter connections that has consistently shown sex differences. We compared FA in 40 transgender men (female birth-assigned sex) and 27 transgender women (male birth-assigned sex), with both homosexual (29 male, 30 female) and heterosexual (40 male, 40 female) cisgender controls. Previously reported sex differences in FA were reproduced in cis-heterosexual groups, but were not found among the cis-homosexual groups. After controlling for sexual orientation, the transgender groups showed sex-typical FA-values. The only exception was the right inferior fronto-occipital tract, connecting parietal and frontal brain areas that mediate own body perception. Our findings suggest that the neuroanatomical signature of transgenderism is related to brain areas processing the perception of self and body ownership, whereas homosexuality seems to be associated with less cerebral sexual differentiation. Nature Publishing Group UK 2017-12-20 /pmc/articles/PMC5738422/ /pubmed/29263327 http://dx.doi.org/10.1038/s41598-017-17352-8 Text en © The Author(s) 2017 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Burke, Sarah M.
Manzouri, Amir H.
Savic, Ivanka
Structural connections in the brain in relation to gender identity and sexual orientation
title Structural connections in the brain in relation to gender identity and sexual orientation
title_full Structural connections in the brain in relation to gender identity and sexual orientation
title_fullStr Structural connections in the brain in relation to gender identity and sexual orientation
title_full_unstemmed Structural connections in the brain in relation to gender identity and sexual orientation
title_short Structural connections in the brain in relation to gender identity and sexual orientation
title_sort structural connections in the brain in relation to gender identity and sexual orientation
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5738422/
https://www.ncbi.nlm.nih.gov/pubmed/29263327
http://dx.doi.org/10.1038/s41598-017-17352-8
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