MSH: A developmental defect in which a TESTIS or both TESTES failed to descend from high in the ABDOMEN to the bottom of the SCROTUM. Testicular descent is essential to normal SPERMATOGENESIS which requires temperature lower than the BODY TEMPERATURE. Cryptorchidism can be subclassified by the location of the maldescended testis.,CSP: failure of testes to descend into scrotum.,NCI: A condition in which one or both testicles fail to move from the abdomen, where they develop before birth, into the scrotum. Undescended testicles may increase the risk for development of testicular cancer.,NCI: The failure of one or both testes of a male fetus to descend from the abdomen into the scrotum during the late part of pregnancy. If not surgically corrected in early childhood, males may be at increased risk for testicular cancer later in life.