Current management of the undescended testis.

True undescended testes are unilateral in approximately 80% of cases, are rarely corrected by human chorionic gonadotropin (hCG), and should be treated by orchiopexy before the patient reaches the age of 3 years to permit optimal tubular development and sperm function. A cryptorchid testis does not mature normally after the age of 2 years and may produce adverse effects on the contralateral descended testis. The higher a cryptorchid testis resides above the scrotum, the more dysgenetic the morphology is likely to be. Hypoplastic cryptorchid testes should be removed early, and high-positioned testes that have not been surgically placed into the scrotum before midadolescence generally should be removed.