Prenatal hormones and sexual orientation Only 23% of childhood gender problems will result in transsexuality in adulthood. Drawing on some transsexualism cases, Garcia-Falgueras and Swaab state that "[f]rom these examples it appears that the direct action of testosterone on the developing brain in boys and the lack of such action on the developing brain in girls are crucial factors in the development of male and female gender identity and sexual orientation ... ." Countless studies have been run on peripheral levels of sex steroids in male and female homosexuals, a considerable number of which claimed to find "less 'male hormone' and/or more 'female hormone' in
Sexual Preference (book) Sexual Preference (book) Sexual Preference: Its Development in Men and Women (1981) is a book about the development of sexual orientation by the psychologist Alan P. Bell and the sociologists Martin S. Weinberg and Sue Kiefer Hammersmith, in which the authors reevaluate what were at the time of its publication widely held ideas about the origins of heterosexuality and homosexuality, sometimes rejecting entirely the factors proposed as causes, and in other cases concluding that their importance had been exaggerated. Produced with the help of the American National Institute of Mental Health, the study was a publication of the Institute for