The news item from National Geographic is about: The bulldog may be a symbol of strength and tenacity, but more than a century of selective breeding has weakened the once-tough canine. The dogs have breathing, skeletal, and skin problems, and, even worse, many can't naturally mate or give birth. If they develop breathing difficulties early, it's unlikely they will make it past the age of five. ... To Adam Boyko, a geneticist at the Cornell University College of Veterinary Medicine, the new research shows a classic dog-breeding story.