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. A baby boy can start to lose the ability to make sperm by 12 months of age. Getting the testicle down into the scrotum early in life can help him have a better chance of having children when he grows up. Second, an undescended testicle is more likely to develop a tumor.