Hip displaysia is genetic. Just because the parents did not show does not mean that the grandparents somewhere didn't have it.

This is part of breeding for the BETTERMENT of the breed. Breeders try to keep from passing these genes, but it is not always possible. If a reputable breeder has not had a problem with these sort of medical historys in some time, then the process is working. If they find a problem, they go back on the pedigree, monitor the litters from these lines, and see how they fair. They also contact others in their circles to advise them of their findings. This is to ensure proper information is desiminated and to avoid breeding others in the same pedigree if the problem is extreme.

If they are reputable breeders, most of them will pay the medical expenses of having them nuetered, compensate the difference, allow for a discount on another pup, and or take them back for full refund. AGAIN ONLY IF THEY ARE REPUTABLE BREEDERS.

A reputable breeder is one who is willing to do anything to save their pedigree. This includes but not limited to, maintaining contact with the dog after sale, can remove a pet from a home if they deem the home is unfit or unsafe, or if the breeder finds that the purchaser is breeding without proper consent is deemed to be irresponsible. They have very thorough contracts that outline specific responsibilities of the owner and the privileges of the buyer.