What most hobby breeders fail to recognize is that even though Yorkies are too cute and adorable and easily sold, JRT's cute easily sold, Chihuahuas the same thing... and all the designer mutts being bred and sold now, these dogs wind up at the shelters in very large numbers on a daily basis. Unless YOU spay or neuter these dogs before your sell them, you cannot guarantee that their offspring (or themselves even, REGARDLESS of what your contract says) will not be in the shelter looking for homes.
Back to the sad reality, I just had another call from the shelter... no, I'm full of other dogs rescued from the shelter and I have no foster homes, so this dog got the needle as soon as they rec'd my reply.
THIS breaks our hearts on a daily basis, and to see more dogs bred adds to it. If you've never walked through the shelter and talked to the techs that do the killing, try it sometime, see if your opinion changes.
Oh and guess what, these small dogs are every bit as hard to get adopted as the big dogs I rescue, why? Because many of them aren't good with children, especially once they have hit the shelter system.