What is it called when a baby's testicles don't drop at birth?

Answer 1

Cyptorchidism, or undescended testicles, is a congenital condition of infant males characterized by one or both testicles that haven't moved into the scrotum by birth. The testicles begin inside the abdominal cavity and, usually before birth, push through the groin tissue forming a scrotal sac. Occasionally, one or both testes do not descend into the scrotum by birth but may come down later.

http://www.hmc.psu.edu/childrens/healthinfo/c/cryptorchidism.htm