Dawnwatch also has a persuasive argument that this sort of law advances the interests of animals more than Denver's outright ban of pitballs:
As California kills hundreds of thousand of dogs every year in shelters, most true animal advocates would be thrilled to see compulsory spay/neuter of all breeds as long as there are any dogs dying for lack of homes. Why not start with those breeds deemed dangerous, that tend to attract those who enjoy organizing dog fights for sport? I write that as the adoptive mother of a sweet little red-nose pitbull, who is, of course, spayed. But thousands of her relatives die every year in California shelters and countless others die in organized dog fights. A ban on breeding them would be wonderful. And it is no doubt the compromise needed that will prevent a misguided over-reaching law like that in Denver, which takes loving dogs out of loving homes.