Is there any statistical proof that 1 inbreeding could cause heart defects ?....the myths surrounding inbreeding are never based on fact....whenever people talk of inbreeding in dogs they compare it to inbreeding in humans...and its so unrealistic its just not worth comparing.....ive seen dogs bred for generations from close families that are very inbred with no physical problems....the important part is being extremely selective on the individuals you breed from.....a father daughter,even a brother sister mating from scatterbred or crossed dogs is inbreeding yes,but is nowhere near as tight