i really don't see anything wrong with mixed breeds. all dogs were mixed with something somewhere along the line where do you think all the breeds came from and they became recognized akc breeds over time. i think mixed breeds are healthier because there is a less of a chance of inbreeding. even if the dogs are not related your going to produce the same old issues the breed is known to have. like yorkies have bad teeth if you breed a yorkie with a dog known to have good teeth you can possibly cancel that out. Like how they mix a pug with a beagle a (Puggle) pugs have horrible breathing problems i owned a pug when i was young and he could never breath. with them mixing the pug with the beagle the puppies now have longer snouts and can breath a whole lot better. not to mention they are cute. But i mean nothing is certain humans have unhealthy baby's so do dogs its just life. and did you know yorkies use to be 30 pounds way back in the day and now look at there size someone somewhere was breeding the smaller sized dogs. to get what we have now. so i don't get why people freak out that people are trying to make a breed smaller its been going on forever. i have three very small yorkies and all healthy. we only hear about the bad with everything but there is more good than bad. there are more dogs with loving homes than dogs that don't have homes. i think the government should really step in and fully check people and make them get a license to even breed a dog once. I think that should also go for human baby's too but all dogs are mutts in a way they all somehow came form a wolf. this is some info on how a yorkie became to be i thought was interesting
Dog Breed History: The Yorkshire Terrier by Susan Bailey