Cryptorchidism is the absence of one or both testes from the scrotum. The word is from the Greek , kryptos, meaning hidden , orchis, meaning testicle. It is the most common birth defect of the male genital. About 3 % of full-term and 30 % of premature infant boys are born with at least one undescended testis. However, about 80 % of cryptorchid testes descend by the first year of life (the majority within three months), making the true incidence of cryptorchidism around 1 % overall. Cryptorchidism may develop after infancy, sometimes as late as young adulthood, but that is exceptional.

Answer this question: failure of the testes to descend into the scrotum at birth? Let's give stream of consciousness first:
The relevant information is: Cryptorchidism is the absence of one or both testes from the scrotum.
So, the final answer is Cryptorchidism.