Yes, my Starr also had this problem. It's called cryptorchidism. He ended up being what I'd call spayed and neutered. They had to go in and remove the testicle which hadn't descended yet and he had many stitches from his belly all the way up to his chest. The other testicle had descended so it was very easy to remove. He had to wear an e-collar until his stitches were removed.

Some vets and people would say to try to wait until both testicles have descended but I couldn't because he was becoming very aggressive. I also didn't want him to start spraying which may happen in uneutered males. Good luck.