As a hybrid breed, their history is short. Generally, Puggle breeders aim to breed one generation of Puggle from purebred Pug and Poodle parents. This is to take advantage of "hybrid vigor" and the Heterosis effect which results in a healthier, more vigorous dog with a reduced chance of genetic disease. Pure breeds and inbreeds often carry genetic disease. Heterosis is the phenomenon where crossing two inbred lines can yeild a progeny with superior genetic constitution. This increased health and vigor does not create a superior breed, but the advantages obtained from it is what produces hybrid vigor. This goal in this scenario is not to create a new breed, but to create a happy and healthy pet.