Androgens and sexual behavior.

Sexual behavior in humans may be classified according to gender role, gender identity, and gender orientation. Sexually dimorphic behavior in humans is generally felt to be determined by postnatal socialization. Recent work in laboratory animals shows that sexual behavior is a function of circulating steroid hormones, particularly androgens. Testosterone given during a critical period in prenatal or immediate postnatal life causes permanent organizational effects on brain structure and function in laboratory animals. Studies in human patients with testicular feminization, 5-alpha-reductase deficiency, congenital adrenal hyperplasia, or prenatal steroid hormone exposure, provide clinical examples of possible effects of prenatal hormone action in the brain as opposed to postnatal socialization. However, these studies do not permit a clear assessment of the role played by either prenatal steroid hormones or postnatal socialization factors in the ultimate expression of sexual behavior in humans.