Normal and abnormal female sexual differentiation

At fertilization, genetic sex determines the orientation of sex differentiation. The genital and urinary systems are closely related embryologically and their common origin is the mesoderm. Primordial germ cells migrate through extra-embryonic tissues into the primitive gonad. Differentiation of the gonads precedes the differentiation of the internal tract and then the differentiation of the external genitalia. Although no gene for female orientation has been identified, genes involved in the different steps of genital tract development in females have been discovered. Some are also implicated in sexual differentiation defects in women, shedding light on the mechanisms that underlie congenital genitourinary malformations. To date, many questions remain unanswered.