Health of crossbred dogs depends on their being descended from healthy parents. Breeders who select their breeding stock for cost-effectiveness and who skip health testing for the same reason will not produce puppies that are as reliably healthy as those bred by more conscientious breeders. However, studies of longevity in dogs have found some advantage for crossbreeds compared to purebred dogs. In general it is believed that crossbred dogs "have a far lower chance of exhibiting the disorders that are common with the parental breeds. Their genetic health will be substantially higher."