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
Follicle-stimulating hormone insensitivity lack of production of sex steroids by the gonads despite high circulating levels of gonadotropins), reduced or absent puberty (lack of development of secondary sexual characteristics, resulting in sexual infantilism if left untreated), amenorrhea (lack of menstruation), and infertility in females, whereas males present merely with varying degrees of infertility and associated symptoms (e.g., decreased sperm production). A related condition is luteinizing hormone (LH) insensitivity (termed Leydig cell hypoplasia when it occurs in males), which presents with similar symptoms to those of FSH insensitivity but with the symptoms in the respective sexes reversed (i.e., hypogonadism and sexual infantilism in males