Embryology of the Human Genital Tract

Abstract

Before sexual differentiation begins at 7–8 weeks of gestation, the urogenital ridge develops on the posterior abdominal wall from the intermediate mesoderm. The Wolffian (mesonephric) and Müllerian (paramesonephric) ducts form and the germ cells migrate into the ambisexual gonad as the mesonephros regresses. At sexual differentiation, MIS/AMH, testosterone and INSL3 are secreted to control ductal development, external genital virilisation and descent of the testis.