Loss of the affected animal's parents and siblings from the breeding pool:
When a cryptorchid animal (or animals) appears in a litter, the implication of this is that both of the parents, male and female, must have been carriers of the defective cryptorchid genes, even if the sire did not show any outward sign of cryptorchidism himself. This is due to the recessive way in which the cryptorchid gene(s) is/are thought to be passed down the generations (see section 10c for full details). Additionally, because the parent animals are both carriers of the defect, there is every likelihood that some of the other offspring in the litter (the siblings of the affected animals) may also be carriers of the abnormal genes. Therefore, if control and eradication of the cryptorchidism condition is to occur in a breeding population, the parents of the affected animals, as well as any siblings of the affected animals, should not be bred from. This constitutes a significant loss of breeding potential from that one kennel or cattery.