If a bitch has produced two cryptorchid pups would you withdraw her - and presumably the stud dog too, though that would have to be his owner's decision - from breeding? The pups are now aged 9 months old, both have one descended testicle. This is the bitch's 1st litter and the stud's 3rd (not aware of any cryptorchids he may have produced before this litter). Thank you.

It would seem that it is a recessive trait passed on by both parents, http://www.avalonkennels.net/canine%20chriptorquidism.htm
"Genetic research has shown the likelihood of cryptorchidism to be inherited as a single autosomal recessive gene and to be sex-limited.  Autosomal refers to a chromosome other than "X" and "Y" (which are the ones determining sex, i.e., XX= female, XY= male).  Recessive means that for the trait to express itself it has to be inherited in "double dose", one from the sire and one from the dam. If only one parent passes the trait to the puppy, it will be a "carrier" but the dominant counterpart (inherited from the other parent) will prevail, and the dog will appear as normal. Sex-limited means that if the proper genetic make up happens in a male, the trait will be expressed. That is, the dog will be a cryptorchid. But, the same genetic make up in a female will cause no abnormalities. In other words, only males will show the expression of this genetic make up. These considerations are of significant relevance because they shine the spotlight on the female just as much as the male due to their ability to be "carriers" of the trait.  This also suggests that there can be skipping of generations (sometimes several) before the trait shows up again, and also explains why breeding with apparently normal dogs for several generations still proved ineffective at eliminating the trait."

No it would be counter productive if both have other good qualities. It's a common enough problem but as Brainless says it has to be carried by both parents so therefore another litter to a different dog/bitch may mean none affected at all. My foundation bitch had 3 litters, she had one dog with just one descended testicle in her third litter, none in the others. When her litter sister was mated to the same dog, that litter included several pups with one missing testicle. I kept a bitch pup from that litter of mine with the one affected dog, she's had two litters herself and all testicles were present and correct in a total of 9 dog pups.

My experience is similar to Goldmali, one of my bitches produced a pup with 1 undescended testicle in her 3rd and final litter.  Her daughter from her first litter, a grandaughter and now a great-grandaughter have all been mated too the same dog and all pups produced have been normal. Teh whole picture needs to be considered, factoring this in but not keepign it as the complete focus.