ABSTRACT
Estrogens are involved in normal growth and differentiation of the mammalian female genital tract. In male reproductive tract tissues, the role of estrogens has not been emphasized, mainly because of the overwhelming importance of testosterone, the androgen responsible for male reproductive tract structure and function. In early sex differentiation, the role of estrogens, of either maternal or fetal origin, in male reproductive tract development remains unclear. Although both human and rodent fetuses are bathed in endogenous estrogens, compounds with estrogenic activity are thought to be relatively inactive in the fetal genital system because of their binding to extracellular proteins, conjugation, and metabolism to inactive forms. Therefore, the focus has remained on androgens, not estrogen, as the hormone responsible for growth and development of male reproductive tissues.
