I have a lot of experience with dogs and am convinced a dog is only as good as the owner that trains them.
While I'm sure nurture is the predominant factor in determining a dog's disposition, I think it's just a proven fact that certain dogs are more aggressive than others. There are more examples of domesticated pit bulls "snapping" and attacking babies and children than there are with other breeds, for example. I don't think that's a coincidence; it's common sense that certain dogs that have been bred for their aggressiveness and killer instinct for centuries would retain some of that.
And I am not saying that there aren't certain breeds that have aggressive tendencies. Quite the opposite. If you read the thread I say that those dogs require more experienced dog owners. Owners that can train those breeds properly so that the aggressive tendency that is in them does not come forth.
The problem is, especially in urban areas, pit bulls are owned by people as protection and as a status symbol. Most of these people are clueless as to the amount of day in and day out routine, exercise, discipline and training these breeds need. When the dogs don't just listen to them they use violence as a training technique which teaches the dog aggression as an answer.
It really is sad that this excellent breed is now being so misused and that people have gotten such a bad idea about these dogs. Boxers, 80 years ago were some of the most ferocious dog fighting dogs there were. They were bred specifically for dog fighting. Today they are widely regarded as the best family dog breed due to their loyalty and love of children and ability to train easily. Pit bulls, for all their aggressive reputations are very intelligent dogs. Not Poodle or Jack Russell Terrier intelligent, but very intelligent. The breed is fairly young and needs to be handled properly so that the aggressive nature is eventually bred out.
I just think to outlaw the breed is ridiculous. The problem is with the dog factory type kennels that breed the pit bulls and sell them to anyone. This type of crap is the problem. Proper pit bull breeders are a lot more selective as to who they sell their litters to.