Lots of good advice. As a bitch owner I’d probably not consider breeding with a dog with an undescended testicle. In my country it wouldn’t be permitted anyway. Not to say you couldn’t but unless he was exceptional in the show ring (which is unlikely as he’s currently only got one) I can’t imagine bitch owners flocking to your door. The ones that might probably wouldn’t be the ones you’d want. Give it time, hopefully it’ll all come right.