Sickening isn't it? I was shocked beyond belief. Where is their proof? Some Time Mag. article on one site!
Here's an interesting article I ran onto trying to find the George Padgett, DVM, study he spoke about in Dog World, where he apparently stated his studies did not show mixed-breed or cross-breed dogs were superior gentically at all. See the last page of this article.
http://www.westwinddogtraining.com/hybridvigor.pdf