As a species, we are extremely adept at making other species extinct, albeit accidentally sometimes. I don't think all xl Bully types should be euthanized, but all existing dogs should be neutered/spayed, and muzzles worn at all times outside. There are 3 adverts on gumtree, within 5 miles of my postcode selling xl puppies, or rather 2 selling xl, one selling xl crossed with a rottweiler (won't that be a cuddly, harmless little addition to the family!) I find that very disturbing. The only way to stop cross breeding and creating another monster dog, is to render the breed incapable of procreation. Banning them will never be entirely successful, but it will reduce numbers.