My dog has one retained testicle as well. It was disclosed prior to my purchasing him. In my dogs case his testicle is in his abdomen. We are going to neuter him at 12 months and they will removed the retained testicle. Sometimes the retained testicle is in the canal and can be worked down.
I went to a reproductive specialist vet to get their opinion and my options.
Dogs with retained testicles should not be bred. They will pass this trait on to their puppies. I was told to get the testicle removed by 12 to 18 months. The cancer risks increase after they are 2 years.
Riley - 11/05/2012-8/30/2013 (Myasthenia Gravis)
He will always be in my heart.