Undescended Testicle. Normally the testicles, which form inside the abdomen of a male fetus, descend into the sac beneath the penis (scrotum) by the time the baby is born.An undescended testicle (cryptorchidism) is one that remains inside the body and has not moved down into the scrotum. One or both testicles may be affected.Undescended testicles are often classified according to their location and whether they can be felt (palpable or nonpalpable).ndescended Testicle. Normally the testicles, which form inside the abdomen of a male fetus, descend into the sac beneath the penis (scrotum) by the time the baby is born.