Mixes are going to happen, but they should be happening with less regularity (note: should!), not more. Mixed pets make great pets. But should they be bred?
I agree the mixed pups should be given the same love and opportunities as the pure breds, but lets face it, anyone who's ever gone to a pound can attest to the ratio of mutts to pure bred (approx 99.5%/.5%). Hence, spay or neuter EVERY pet that's not intended for breeding as early as possible to avoid the mistakes that result in another litter of pups ending up at the pound.
And I've got little problem with people required to obtain some form of 'license' before breeding to sell pets, with financial penalties for unlicensed breeders. Poorly bred pets can be potentially dangerous! (As I suppose most any 'pet' could be). At least a person 'licensed' could be required to have training in quality breeding practices, health testing requirements, etc. This could help assure more healthy breeds (less undesirable traits/genetic health issues passed on), etc.
-Krag