SOC 152A Lecture Notes - Lecture 19: Sexual Differentiation, Twin Study
Document Summary
Animals are gay, they have sex with whatever animal regardless of sex, unless to reproduce. Evidence for a biological influence on sexual orientation. Twin studies suggest a genetic influence, especially in men. Shared by twins even if they were reared separately. Study: studied twin concordance rates for sexual orientation = percentage of same-sex co-twins of gay probands who are themselves gay. Not 100% that twins will both be gay. Prenatal testosterone influences the sexual differentiation of the brain (driving towards typical male direction when testosterone levels are high) The sexual differentiation leads to gendered traits including sexual orientation. Homosexuality is linked to a spectrum of gender-atypical traits, especially in childhood. Animal models of homosexuality can be generated by prenatal hormonal manipulation. Women with congenital adrenal hyperplasia (exposed to high levels of male hormones prenatally ) have increased likelihood of same sex attraction and experience. Lesbian and gay men are atypical physiologically and anatomically in some traits, suggesting atypical hormone exposure.
