Although encountered not infrequently by gynecologists and urologists, anomalies limited to mullerian or wolffian derivatives have received relatively little attention from geneticists. Despite a paucity of formal investigations, heritable tendencies seem apparent in several abnormalities. In this review we delineate selected disorders and comment upon certain clinical and genetic aspects. Not considered are those disorders of sex differentiation in which there are abnormalities of either gonads or external genitalia, in addition to abnormalities of the internal ductal system. Prior to discussion of these disorders, a review of a few salient features of reproductive embryology is given.