Normal Gonadal Development

The development of the reproductive system is closely associated with the urinary system in both males and females. Formation and differentiation of gonads in either sex, is dependent on the arrival of the germ cells into the gonadal ridge on the medial side of the intermediate mesoderm. The primordial germ cells for a male fetus carry XY chromosome, while XX chromosome for female fetus. Lateral to the developing gonads and the mesonephric ducts, the coelomic epithelium invaginates in the urogenital ridge to form Müllerian/Paramesonephric ducts at 5 weeks of gestation. The presence of testosterone in the male fetus causes the paramesonephric duct to degenerate except where it forms the appendix of the testis. In female fetuses, the presence of estrogen and absence of testosterone favors the formation of the internal reproductive organs of females. The chapter describes the development of male and female reproductive system in detail.