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
Transgender hormone therapy (male-to-female) to a higher boost in plasma estradiol levels; however, the long-term side effects haven’t been studied and the safety of this route is unclear. As with any pharmacological or hormone therapy, there are potential side effects, which in the case of transgender hormone therapy include changes in sexual functioning. These have the ability to significantly impact sexual functioning, either directly or indirectly through the various side effects, such as cerebrovascular disorders, obesity, and mood fluctuations. In addition, some research has found an onset of diabetes following feminizing hormone therapy, which impairs sexual response. Whatever route an individual and their doctor