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
Persistent Müllerian duct syndrome deficiency of fetal anti-Müllerian hormone (AMH) effect due to mutations of the gene for AMH or the anti-Müllerian hormone receptor, but may also be as a result of insensitivity to AMH of the target organ. Persistent Mullerian Duct Syndrome (PMDS), also known as Persistent Oviduct Syndrome, is a congenital disorder related to male sexual development. PMDS usually affects phenotypically normal male individuals with the karyotype (46, XY) and is a form of pseudohermaphroditism. PMDS has various causes to do with AMH or receptors abnormalities. For example, AMH has failed to synthesis, failed to release or was secreted at the wrong