Cryptorchidism is when one or both testicles fail to descend into the scrotum. This condition is a fairly common problem in dogs, cats and other animals. People often wonder why animals that are cryptorchid need to be neutered. The reason is two-fold. Animals that are cryptorchid may still be fertile, especially if unilaterally (one-sided) cryptorchid. Cryptorchidism is a known heritable trait. This condition is more common in some breeds, but seen in all breeds and is passed on from father to (male) offspring.

In addition to the heritability aspect, the testicle (or testicles) that remain in the abdomen are more prone to cancer or torsion (twisting and cutting off blood supply).

When should my dog or cat be neutered?
Opinions will vary, but if your dog or cat is still cryptorchid (one or both testicles) by 6 months of age, it is highly unlikely that the testicle(s) will ever drop, and the animal should be neutered to prevent testicular tumor formation and passing on this genetic trait to future generations. If the testicle is not readily palpable in the inguinal canal (groin area), abdominal exploration is necessary to find the retained testicle.