[bchgirl]

Originally Posted by Ladymom

Actually, designer mixes don't have hybrid vigor because the breeds often share the same predisposition to certain genetic conditions. For example, both Maltese and Yorkies are prone to liver shunts, so if they are bred irresponsibly without genetic screening and health testing, they have just as much chance of producing a puppy with a shunt than two parents of the same breed. In fact, they have a much greater chance of genetic conditions as responsible breeders don't breed mixes. "Hybrid Vigor" is a myth perpetuated by these greeders.

Please read these articles:

Hybrid Vigor Myth

Hybrid Vigor

During a seminar I attended by Dr Center...we were told that mixing the two breeds introduces any genetic default in either given breed.