That is called line-breeding. When there are common ancesters. Many of times, you can get some very nice puppies. It is not recommended that this be done over and over because you increase your risk of duplicating a non-desired trait. It is not detramental to the puppy. You would have to look at the puppy to evaluate for those types of situations.
Answered by afaust1 - 1/2/2012 1:26:38 PM