I think that no dog, what ever the breed should be left alone with anyone. Any dog can snap, even if it's normally a friendly and cheerful dog, you never know, unless you can speak dog! Pitbulls were bred for fighting so I think they shouldn't be trusted with babies etc. When they are puppies, they should be well socialized with other dogs and humans to prevent the risk of aggression. This really should be used with any dogs!