It sounds like you are describing undescended testicles, also known as cryptorchidism. It is a relatively common birth defect in which one or both of the testicles do not fully descend into the scrotum. In most cases, the testicles will descend on their own within a few months of birth, but in some cases, surgery may be needed to move the testicles into the correct position.
Undescended testicles can affect fertility and increase the risk of testicular cancer, so it is important for boys with this condition to be monitored and treated as needed. In some cases, hormone therapy may be used to stimulate the descent of the testicles, and in more severe cases, surgery may be necessary to move the testicles into the correct position.