If this doesn't happen after three or four months, it may need to be treated by a doctor. Your doctor can tell if your baby has an undescended testicle by checking the baby's scrotum. A nonpalpable testicle might be inside the abdomen, or too small to feel or not there at all. It's important to find out which one is the reason. Unfortunately, an x-ray can't tell if a nonpalpable testicle is inside the abdomen.
Doctors usually have to do surgery to find out.
There are two reasons to treat an undescended testicle. First, undescended testicles may not make sperm. Testicles are in the scrotum because the temperature there is cooler than it is inside the body. A cooler temperature helps the testicles make sperm. A man's ability to make sperm can be lost in early childhood if the testicle doesn't drop down into the scrotum.