Failure to descend can result in sterility. Impairment of germ cell maturation and subsequent infertility in adulthood are well-recognized consequences of cryptorchidism. The incidence of azoospermia in unilateral cryptorchidism (one undescended testicle) is 13% and this figure increases to 89% in untreated bilateral cryptorchidism, making cryptorchidism the most common etiologic factor of azoospermia in the adult. Reports have suggested that surgery can be performed before the age of one to minimize germ cell loss, as fertility index (number of spermatogonia per tubule) is adversely affected in boys with cryptorchid testes beyond a year.