Intrauterine gonadal development.

This review article summarizes the intrauterine gonadal development and differentiation of both male and female human embryos and fetuses. It describes in detail (1) the organization of the indifferent gonad and its seeding by the extra-gonadal germ cells, (2) the development of the duct systems before sex differentiation, and (3) the controlling mechanism of differentiation of the ovaries and testes. Timetable for the development of the human male and female reproductive systems have been compiled from the literature.