The neurodevelopment of human sexual orientation

Rahman, Qazi

doi:10.1016/j.neubiorev.2005.03.002

Cited by 109 publications

(98 citation statements)

References 90 publications

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“…We proposed a phenotype dissection of neuropsychic human sexuality into: sexual identity, sexual orientation (which we consider rather as the configuration of sexual appetence or dia-morpho-philia), sexual psychomotor form, sexual somatic connection, genital connection, and sexual integration in the whole personality (Valenzuela, 1993(Valenzuela, , 2006. In the last 20 years, two lines of study have found a reliable basis for understanding the biology of human psychosexual development and SR heterogeneity: (1) Human mutants of "sexual" hormones or their metabolism point to the prenatal role of androgens conditioning maleness of the brain, sexual identity and sexual orientation (Hines, 2004;Rahman, 2005;Bocklandt and Vilain, 2007). (2) There is a consistent association among the number of older biological brothers (fraternal birth order, FBO), handedness, SR of siblings and male homosexual orientation (Blanchard and Bogaert, 1996;Zucker et al, 1997;Cantor et al, 2002;Blanchard, 2004Blanchard, , 2006Lippa, 2006, 2007).…”

Section: Introductionmentioning

confidence: 99%

Sexual orientation, handedness, sex ratio and fetomaternal tolerance-rejection

Valenzuela

2010

Biol. Res.

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Fraternal birth order (FBO) appears as a prenatal cause of 15% of homosexual males (gays) through mnemonic maternal anti-male factors. Non-right-handed men seem to be protected from homosexuality. Four hypotheses are proposed: (1) androgenic factors of nonright-handedness neutralize anti-male factors; (2) non-right-handedness and homosexuality are lethal or produce mental impairment; (3) non-right-handed male embryos are insensitive to anti-male factors; (4) mothers of non-right-handed fetuses do not produce antimale factors. Studies of the sex ratio (SR) of older and younger siblings show: (1) a significant heterogeneity in the SR of siblings of right or non-right handed heterosexual men and women; (2) lesbians are born among siblings with high SR; (3) siblings of righthanded gays show a higher SR than non-right-handed gays that present a low SR. Based on our discovery of maternal tolerancerejection processes, associated with genetic systems (ABO, Rh), where zygotes or embryos different from their mother induce better pregnancy and maternal tolerance than do those that share antigens with their mothers, I propose a new explanation for sexual relationships, sexual orientation, handedness and sibling SR. Lesbian embryos could induce tolerance from mothers with anti-female factors. Non-right-handedness could induce maternal tolerance, or change the maternal compatibility of "gay" embryos. Alternatively, gay embryos could be poor inducers of maternal tolerance towards male traits.Key terms: homosexuality, handedness, sex ratio, birth order, fetomoternal tolerance, genetic distortions biological brothers, reared together or apart from the index homosexual case, are responsible for FBO effect. The probability of being homosexual increases as the number of older brothers increases. Handedness interacts with homosexuality and the SR of siblings; homosexuality, due to FBO, affects non-right-handed men less (Blanchard, 2001(Blanchard, , 2004Blanchard and Bogaert, 1996;Cantor et al., 2002;Bogaert, 2003Bogaert, , 2005Bogaert, , 2006, a relationship explained hypothetically by four prenatal mechanisms Lippa, 2006, 2007;Blanchard, 2008): (1) androgenic factors associated with non-right-handedness could cancel maternal anti-male factors leading to homosexuality; (2) homosexuality and non-right-handedness together may lead to death, neuro-psychic impairment or any condition that confers a low probability of being ascertained; (3) non-right handed fetuses my be insensitive to maternal anti-male factors; (4) mothers of non-right handed fetuses do not produce anti-male factors. The FBO was found also in transsexuals whose sexual identity, rather than their sexual orientation, is altered (Green, 2000). These hypotheses are in contradiction with the fact that non-righthandedness is more frequent in homosexual men (gays) and women (lesbians) than in heterosexuals (Lalumiére et al., 2000; this study). A hypothetical reconciliation of these contradictory facts was presented by Blanchard (2008). The authors (of the FBO hypoth...

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Section: Introductionmentioning

confidence: 99%

Sexual orientation, handedness, sex ratio and fetomaternal tolerance-rejection

Valenzuela

2010

Biol. Res.

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“…Some researchers focused on the organizing effect of prenatal sex steroid hormones and the key role of hypothalamus. They insisted that sexual orientation is determined during early development, as well as the physiological gender, and left little room for learning models of sexual orientation Rahman, 2005;Savic, Garcia-Falgueras, & Swaab, 2010;Swaab, 2004). However, their hypothesis is not compatible with the clinical data and genetic research findings (Davis et al, 1996;Friedman & Downey, 2010;Joel, 2011;Langstrom, Rahman, Carlstrom, & Lichtenstein, 2010), and our case presentation.…”

Section: Discussionmentioning

confidence: 58%

The Change of Heterosexual Preference in Adolescents: Implications of Stress and Cognitive Regulation on Sexual Orientation

Zhu¹,

Ren²,

Cao³

et al. 2013

JSS

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Sexual orientation is a complex area. It is unclear to date how people precisely establish their preferred sexual objects. This paper presents two cases, whose heterosexual preference were changed in late adolescent age after a severe psychological event, to draw attention to the study of the possible underlying mechanism. Case 1, one identical male twin, was seriously punished at age 12 years, as he loved a girl in his classroom. Afterwards, he feared to contact with girls, and became attracted to young men at age 17 years, and kept same-sex sexual behaviors since then. However, his twin brother is always heterosexual. Case 2, a girl at age 16 years, was unexpectedly betrayed by her boyfriend, she bore great pain and distress in the beginning. Since then, she had a definite opinion that men were unbelievable, and gradually turned her heterosexual preference and had same-sex sexual behaviors with a girl classmate more than 3 years. Our case presentation indicates that severe frustration of primary heterosexual desires or behaviors and the successive cognitive regulation might lead susceptible adolescents into reorienting their sexual preference. The role of prefrontal cortex and related neuromodulatory pathways were discussed.

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“…There are many theories about the determination of sexual orientation, but increasing evidence suggests that it is determined by a conjuncture of factors, such as genetic (Burri, Cherkas, Spectos, & Rahman, 2011;Hamer, Hu, Magnuson, Hu, & Pattatucci, 1993;Whitam & Matrhy, 1991), neurobiological (Rahman, 2005;Diamond & Dickenson, 2012;Burke, Manzouri, Dhejne, Bergstrom, Arver, Fausner, & Savic-Berglung, in press), hormonal (Balthazart, 2011;Leinung & Wu, in press), cultural (Green, 2000;Kulic, 2009) and psychological, such as Bem's (1996) theory on how child`s preferences on sex-typical or sex-atypical activities and peers may influence sexual orientation in adulthood. Such rapid changes are unlikely to have a genetic basis and suggest psychological and cultural modifications in the person-environment relationship, although biological factors cannot be completely excluded.…”

Section: Discussionmentioning

confidence: 99%

Trends in sexual orientation in Brazil

Carvalho

Dall’Agnol

Lara

2017

Psico

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Este artigo está licenciado sob forma de uma licença Creative Commons Atribuição 4.0 Internacional, que permite uso irrestrito, distribuição e reprodução em qualquer meio, desde que a publicação original seja corretamente citada. http://creativecommons.org/licenses/by/4.0/deed.pt_BR Artigo originAl ISSN 1980-8623 AbstractThe current study aimed to evaluate the prevalence of sexual identities in Brazil across age and sex based on five categories (heterosexuals, mostly heterosexuals, bisexual, mostly homosexuals, and homosexuals) and to assess homoerotic ideation and behavior in heterosexuals. The data were collected using self-report questionnaires in a research website. Data from 41,873 participants were collected and analyzed. From total sample, 78.2% of males and 89.8% of females self-declared to be heterosexuals. The most prevalent minorities were homosexuals (4.6%) and mostly heterosexuals (4.1%). Same-sex ideation and behavior among heterosexuals was frequent and gender differences were robust. Orientation identities other than substantial heterosexuals seem to be more prevalent in the younger generations.Keywords: sexual minorities; sexual orientation identity; Internet research methods; gays, lesbians and bisexuals. Tendências da orientação sexual no Brasil ResumoAvaliou-se a prevalência de identidades sexuais em homens e mulheres de diferentes gerações com base em cinco categorias (heterossexuais, predominantemente heterossexuais, bissexuais, predominantemente homossexuais e homossexuais) e aferiu-se a ideação e comportamentos homoeróticos em heterossexuais. A coletada de dados foi realizada por meio de questionários de autorrelato disponibilizados em um sitio de pesquisa na Internet. Dados de 41.873 Brasileiros foram colhidos e analisados. Do total, 78.2% dos homens e 89.8% das mulheres se declaram heterossexuais, a minoria sexual mais prevalente foi a de homossexuais (4.6%) e de predominantemente heterossexuais (4.1%). Ideação e comportamentos homoeróticos em heterossexuais foram frequentes e diferenças entre homens e mulheres foram robustas. Não heterossexualidades foram mais prevalentes em gerações mais jovens.Palavras-chave: minorias sexuais; orientação sexual; métodos de pesquisa pela internet; gays, lésbicas e bissexuais. Tendencias de orientación sexual en Brasil ResumenSe evaluó la prevalencia de las identidades sexuales en hombres y mujeres de diferentes generaciones sobre la base de las cinco categorías (heterosexuales, predominantemente heterosexuales, bisexuales, predominantemente homosexuales y homosexuales) y la ideación y conductas homoeróticas fueran evaluadas en heterosexuales. Los datos fueron recolectados a través de cuestionarios de autorrelato en un sitio de pesquisa en la Internet. Se recogieron y analizaron datos de 41.873 brasileños. Del total, el 78,2% de hombres y 89,8% de las mujeres dicen que son heterosexuales, la minoría sexual más prevalente era homosexual (4,6%) y predominantemente heterosexual (4,1%). Ideación y conductas homoeróticas en heterosexuales fueran comune...

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The neurodevelopment of human sexual orientation

Cited by 109 publications

References 90 publications

Sexual orientation, handedness, sex ratio and fetomaternal tolerance-rejection

Sexual orientation, handedness, sex ratio and fetomaternal tolerance-rejection

The Change of Heterosexual Preference in Adolescents: Implications of Stress and Cognitive Regulation on Sexual Orientation

Trends in sexual orientation in Brazil

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