As was said above, certain breeds are predisposed in teh DNA's to be aggressive. Sure, most any dog will be a great pet and good around people if it's raised in a loving environment. But there are no guarantees with some breeds. Chows are a dog in that group. We had a couple and they were raised from puppies like they were one of our children. But, extremely protective of us and I was always wary of my own dog around other kids. If a poodle is startled or pet the wrong way and takes exception to it, it's, "Damn, your dog bit me". If a pit takes exception, it's, "Call 911".