Posted 21 February 2012 - 10:16 AM
As I understand it, true monorchidism, meaning that the dog only has one testicle, the other one does not exist anywhere in his body, is rare. What we see most of the time, is one or both that did not descend properly. This undescended state is a simple recessive--both parents must carry it to make an affected male puppy. The bitch carries the trait but it apparently does not affect her reproductive state.
I am not advocating breeding this trait. I am just curious about the severity of the issues it causes. I have heard that the one testicle descended condition was sort of common in the conformation breed ring earlier in the 20th century, until the AKC decided it was a disqualifiable fault. The main problem with this condition is that by breeding an affected male to a carrier female, the next generation's males might have no descended testicles at all, which I agree is a very distressing condition and a big mistake humans could make. This "bilaterally cryptorchid" state is the end of the line, reproductively speaking.
The reason I started thinking about missing testicles during the MM/Mm or even why have merles" discussion is this notion of harm. A dog with one testicle can still work, reproduce, have a happy life. A blind and deaf dog, though probably not knowing what he is missing, being born that way and all, is missing out on a lot we humans know make a complete life for a dog. He is also bound to have some difficulty navigating our very complex culture, into which he is born and within which we have very high demands of dogs. We also neuter and spay most of our sport and pet dogs, so a dog with two testicles can be a very rare sight at the average suburban vet clinic.
Just musing. I happen to have a "great working dog" with one testicle that is down and one which isn't. I am his breeder, he's everything I wanted the breeding to produce and more, he is very healthy and easy to live with, and out of the litter, all of whom I have worked, he is my very favorite worker. We have become a very good team, starting out as novice novices as we did. Would I want a puppy from him? You bet. Will I get one, no. I've come this far being concientious to stop now. I think my mulling over these possibilities is a much different discussion than whether to purposely breed an easily prevented deformity or defect for the sake of some "look".