As a baby boy grows inside his mother, he develops testicles.
Early in his development, his testicles are in his belly.
Normally, before he is born, his testicles move down into his
scrotum, the sac that hangs below the penis. When one testicle
does not move into the scrotum as it should, the baby has an
undescended testicle. In rare cases, both testicles It is most
common in baby boys who were born before their due date or who
were very small at birth. Doctors don't really know what causes
an undescended testicle. This common condition runs in some
families (can be Most of the time, the testicle descends (drops)
on its own by the time the baby is 3 months old. If your baby's
testicle hasn't dropped by the time he is 6 months of age, your
doctor may suggest testicle doesn't cause pain or other
symptoms. The scrotum may look a little smoother or less
developed on one side, or the side without a testicle may look
smaller and flatter. You can't feel the testicle in the scrotum
on the side where it hasn't descend