CONICET | Buscador de Institutos y Recursos Humanos

Genital sex differentiation involves a series of events whereby the sexually indifferent embryo progressively acquires male or female characteristics in the gonads, genital tract and external genitalia. Normal sex development consists of several sequential stages. Genetic sex, as determined by the chromosome constitution, drives the primitive gonad to differentiate into a testis or an ovary. Subsequently, internal and external genitalia will follow the male pathway in the presence of specific testicular hormones, or the female pathway in their absence. Since the presence of the fetal testis plays a determining role in the differentiation of the reproductive tract, the term "sex determination" has been coined to designate the differentiation of the gonad during early fetal development. Here we review the sexually undifferentiated stage of embryonic development, and the anatomic, histologic, physiologic and genetic aspects of the fetal sexual differentiation of the gonads, the internal reproductive tract and the external genitalia.