The genetics for dogs is the same as humans in this regard. The problem is this--if a brother and sister both have a bad gene that is not dominant, no problem. But with both parents having that gene, there is a chance that gene will be dominant in their baby, you have a problem. Will every puppy from a bother and sister have a problem? No. But why take the chance when it is not necessary? The risks far outweigh any rewards. My opinion in short--don't do it. |