In general, the Scottish Fold is a hardy cat, thanks to its barnyard pedigree.However, a degenerative joint disease has been discovered to be a common by-product of breeding folded-eared cats to other folded-eared cats. When two folded-eared cats are bred together, the dominant gene that causes the folding combines to produce deformities of the spine, hind legs and tail. Ethical breeders will only breed straight-eared Scottish Fold cats to folded-eared Scottish Fold cats, as these animals seldom if ever develop joint disease.