I agree with Chatty -- the only dog that ever attacked me was a 3 lb chihuahua

the pit bull DOES usually play a little harder and can hurt someone just by playing due to their "locking jaws" -- but my german shephard plays pretty rough herself and she has been raised by my pomeranians since she was 3 days old and has NO CLUE she's 60 lbs instead of 6 lbs

you just have to be very careful where you get the pit bull from -- look for a well known breeder that specializes in FAMILY dogs instead of PROTECTION dogs -- and ask for references -- check with the humane society or the district attorneys office to see how many dogs, from that breeder, have been reported as vicious

and you need to get control of the dog immediately - dog training classes - you dont have to beat a dog into submission but they do need to know that YOU are the alpha dog - they can be WONDERFUL family pets if breed and raised in a loving environment

but that can be true for any breed