Familial functional anorchism: a review of etiology and management.

Identical male twins with small penes and bilateral unpalpable gonads were unresponsive to human chorionic gonadotropin stimulation. Both infants had elevated levels of gonadotropins. The size of the penis did not meet fully the criteria for micropenis and the organ was responsive to testosterone therapy. The use of primary human chorionic gonadotropin stimulation followed by testosterone measurements is indicated for children with cryptorchidism in whom the etiology of micropenis is in doubt. We report the first observation of anorchism in identical twins.