Selective breeding for extreme physical traits in companion animals has caused widespread heritable health problems; reform of breed standards and breeding practices is gaining momentum.
Companion animal selective breeding has in many cases produced animals that are simultaneously popular and systemically unhealthy. Brachycephalic breeds sold on the basis of appearance features that are the direct cause of their breathing difficulties, sleep disorders, and exercise intolerance. Chondrodystrophic breeds whose back problems are built into their genetics. Double-merle dogs bred by inexperienced breeders and born deaf and blind. These welfare problems are heritable by design — the traits causing them were selected for intentionally. Reform requires action at multiple levels: breed standard revision, breeding licence requirements that exclude animals with severe heritable conditions, consumer education that reframes flat faces and exaggerated conformations as health impairments rather than desirable features, and veterinary profession advocacy.