disorder in which one or both of the testes do not descend spontaneously to the usual position in the scrotum. (The testes normally descend around the time of the male infant's birth.) Usually only one testis fails to descend into the scrotum; the other, descended testis suffices to ensure the individual's normal male sexuality. Cases in which both testes fail to descend are rare and are more serious, since undescended testes are usually nonfunctional (i.e., produce few or no sperm), and the development of normal male sexuality is thus threatened. An undescended testis remains within the inguinal canal or in the abdominal cavity. Besides being nonfunctional, an undescended testis is more likely to be injured, and the blood supply to it is more likely to be cut off by twisting. Also, testicular cancer is 5 to 10 times more likely to develop in an undescended testis, even if the condition is corrected through surgery
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