Purebreds and inbreeds often carry genetic disease. Heterosis is a theory in which the
phenomenon of crossing two inbred lines can produce descendants with superior genetics and
create a superior breed, but the advantages obtained from it are what produce hybrid vigor.
This goal in this scenario is not to create a new breed, but to create a happy and healthy pet.
Heterosis effect results in a healthier, more vigorous dog with a reduced chance of genetic
disease. It is well known in all domestic animal breedings, hybrids 50%-50% mixes of two
different breeds will raise the chances of having less genetic diseases because all doubling of
detrimental effects will stop in the first generation. The genetic term for this is HETEROSIS
EFFECT. This effect often gives non-related individuals stronger descendants than inbreeds.
Breeders who breed these hybrid dogs have stated their goal was to get healthy and happy
dogs without genetic problems. Most breeders crossing with the poodle are looking for a soft
silky non-shedding coat good for allergy sufferers.
The purpose of these hybrids is not and should never be to develop a new breed. Once one
goes beyond first generation purebred to purebred, you loose the heterosis effect, which is the
goal for most hybrid breeders. It is only in this first generation that dogs could get the benefit
of the greatly demanded HETEROSIS effect, and avoid genetic diseases, which are common
among purebreds and inbreeds.
(from the Dog Breed Info Center)