My eldest had undescended testicles. The one on the left was left alone as when manipulated, it descends to the correct place. The Dr said it was likely that it will descend of its own accord, probably before he starts school.

The right testicle, when manipulated, would not descend to the correct spot and was surgically stitched into place two weeks before DS1's 2nd birthday. It was scary but the staff at the hospital were fantastic. They do not rush into surgery as most of the time (so i was told), the testicles will descend on their own. DS1 was diagnosed when he was 2 months old, so there was a fairly large gap between diagnosis and surgery.

Apparently this is quite common. There is an slightly higher risk of testicular cancer so your son will need to be aware that he needs to check himself when he is older. There is also a slightly higher risk of the testicles twisting which apparently is quite painful. Other than that, he is just like any other little boy.

Surgery is a dangerous thing for anyone, I think, but all the precautions are taken and I felt, personally, that the pros outweighed the cons in our situation.

If you have any questions, feel free to ask.