Why do some dog breeds have so many health problems?
Because dogs have been bred for appearance far faster than any natural process would allow, and several popular looks are directly incompatible with normal function.
The two separate mechanisms, which get conflated:
Conformation problems. The breed standard itself specifies a body shape that causes disease. This is not a breeding accident — it is what the breed is defined as. No amount of careful selection within the breed fixes it, because the shape is the breed.
Genetic disease from a small gene pool. Closed studbooks mean every dog in a breed descends from a limited founder population. Recessive disorders concentrate, and inbreeding coefficients in some breeds are high.
The clearest conformation examples:
Brachycephalic (flat-faced) breeds — pugs, French and English bulldogs, boxers. The skull was shortened but the soft tissue inside was not, so the airway is crowded. Brachycephalic obstructive airway syndrome causes laboured breathing, exercise and heat intolerance, sleep disruption and, in severe cases, collapse. Owners frequently report the snoring and snorting as endearing breed characteristics when they are symptoms of obstruction. Eye problems, dental crowding and skin fold infections follow from the same shape, and many cannot give birth without a caesarean.
Long-backed, short-legged breeds — dachshunds especially — with a high rate of intervertebral disc disease.
Very large breeds, with joint disease and shorter lifespans.
Extreme skin folds, giving chronic dermatitis.
Steeply sloping hindquarters in some lines, associated with joint problems.
Why it persists: demand follows fashion and visibility, popular sires spread their genetics disproportionately, and breed standards change slowly. Several veterinary bodies have campaigned publicly against breeding for these features, and some countries have restricted it.
What buyers can do: check breed-relevant health schemes, favour lines bred for longer muzzles and moderate features, and treat visible breathing noise as a red flag rather than a quirk.