My son was born with his left testicle undescended. He is 15 months old and we have done this operation which was an open cut surgery. His left testis is 1/3 the size of his right testicle. My concern is, will it become normal in growth? Does it would affect his fertility in future?
Thank you in advance
Let's address the extreme case first. Even if his left testicle was damaged because it didn't properly descend, the right testicle has more than enough capacity to make up for the the left testicle. He will develop normally and be fertile as an adult.
The primary concern about an undescended testicle is testicular cancer. "An undescended testicle is more likely to develop cancer, even if it is brought into the scrotum with surgery. Cancer is also more likely in the other testicle" ["Undescended Testicle," MedlinePlus]. Your doctor will keep watch for this during his regular checkups. It isn't something you should worry about, but it is something to be aware of. Sometime after puberty he will need to learn how to check for cancer himself. Usually once he gets past his twenties, the odds of getting testicular cancer drops.
Another problem is testicular torsion. "Testicular torsion occurs 10 times more often in undescended testicles than in normal testicles" ["Undescended Testicle," Mayo Clinic]. Testicular torsion is when the testicle twists on the cord that it suspends from, which cuts off the blood supply to the testicle. If that happens, it is extremely painful, though the pain is mostly felt in the lower abdomen Again, this is more likely to happen during adolescence. Insist that he wears compression shorts or a jock strap for sports. These limit the twisting of the testicles during activity.
Whether the testicle will grow normally or not is not easily predictable. The earlier the operation, the greater the odds that it will recover. It is basically something that just has to be monitored.