Ok, without having read all the posts before me I have to take a stab at answering this one. I have been involved in the "dog world" for as long as I can remember. The Pit Bull is NOT a pure bred dog, it is a variation of a MIX breed. Starting with the American Bull Terrier. Saying that they are Pure Bred is like saying a cockapoo is a pure bred dog, two (or more) different breeds mixed together, without science to follow it and without generations that are left in between to stablize the breed.
That said, any dog, and I do mean ANY dog, regardless of breed, age, height etc can be extremely vicious. I remember friends of the family putting a whole litter of dogs to sleep because they kept attacking and I do mean ATTACKING each other. Better safe than sorry was this breeders point of view.
Many times the dogs that spawn (for lack of a better word) pet pit bulls were dogs that were bred for their vicious nature and intended for fighting. Though fighting dogs is illegal many many people still practice this form of "entertainment".
If you are afraid of the dog or afraid for your children do not go near it, not just a pit bull but any dog. I have seen dogs that though they seemed extremely docile have attacked and almost killed people. Even then the human owners were hesitant to put the dog to sleep.
I have one rule with my own dog (she is 10 now and kind of cranky) if she ever bit one of the kids without provocation (like if they fell on her, pulled her tail, smacked her) she goes to the vet IMMEDIATELY. She considers all my kids her puppies. If that day ever changes and she sees them as rivals then she goes to live with my mother's best friend.
I will definetly have a dog again after her, but after my kids are grown. I hope to get an Irish wolf hound, they are a lovely breed.
BTW, my dog is a sheltie!
Diana