To turn that around, why isn't it ok for Jim and Bob down the street to breed their untested dogs or two dogs that have thyroid problems if it is ok to knowingly breed two merles together? So what? It's ok because people have done it before and because the dogs were working dogs? "Honey, I know I had an affair, but JFK did it AND HE WAS THE PRESIDENT!!!!!". Yea, that works. People used to do and do all kinds of things but that doesn't automatically make it ok, a la the old parents' standby "if all your friends jumped off the Empire State Building, would you?" I call BS. I've seen (sometimes heated) discussions about double merle breedings long before this on various forums. And besides, so what if that really is the reason? You're not allowed to care about the issue because you just learned about it?