pit bulls can actually kill and mame all on their own.
So here's the bottom line, based on my own analysis of the available data. If you want a safe dog, avoid chow chows and German shepherds. Golden retrievers are your best bet. Pit bulls may well be a breed to avoid, but there is not definitive data to support this. Get a female or a neutered male, small, and over five years old. The fewer children around, the less likely it is to bite.
If a dog is going to bite you though, the two breeds you least want it to be are a pit bull or a Rottweiler. They are definitely the most dangerous biters, once they decide they're going to bite you. If you see one on the street, there is not sufficient data to support any particular need for concern. Like all dogs, its owner and its environment are major factors in its level of aggression.
This is a case where the value of good science is to drive policy. Most researchers agree that breed-specific legislation — a nice term for pit bull bans — are inappropriate. No good data exists to demonstrate that such bans have had any impact. Improved enforcement of existing laws, and improved education for dog owners, are far more likely to reduce the number of dog bites, fatal or not.
I'm curious... what would be the proper hosre~dog training be?