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 2 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.