An undescended testicle (cryptorchidism) occurs when a testicle does not move into its proper position in the skin bag that hangs below the penis (scrotum) before birth. Typically, only one testicle is affected. However, in 10% of cases, both testicles may remain undescended.

An undescended testicle is commonly seen among babies born prematurely. Undescended testes usually settle on their own within the first few months of life. However, if your baby boy has an undescended testicle that does not resolve on its own, surgery is the only option.