I have been around a lot of them, really love the breed. I personally would rather have this breed than a german sheperd, akitas, rottweiler, or some of the other large breeds. If it is a very calm, docile, submissive pitbull, who is very well socialized with other animals you don't really have to worry. the ones to worry about are the very dominant, overstimulated, animal aggressive pitbulls. At my shelter that I work at we have to temperment test all dominant breed dogs or aggressive dogs. If its from a shelter I am sure they did a thorough behavioral assessment and owners were informed of all the things common with the breed. As long as the owner is responsible, experienced with the breed, dog is well trained and socialized, and kids are always supervised, not left alone, you should not really worry. Most pitbulls love people and are very sweet. Its the lack of training and early socialization that cause problems, also if the mom of the dog was aggressive , there is a higher likelihood of dog becoming aggressive as well. I think they get a bad rap because of the media fixates on them. I have been attacked by more shepherds personally than pitbulls, but the media doesn't tell you about the other breeds that attack. I was even attacked by a golden retriever believe it or not. All breeds have some aggressive dogs. If you know what to look for in a good pitbull, it's generally not something to worry about. Me personally I would wait until the kids are older, not because of the breed but because pitbulls think they are giant lap dogs and sometimes do not know their own strength, and you can get hurt unintentionally by them jumping on you or pulling at the leash hard. Again for this reason children should always be supervised, but i would advise this of any large animal, because afterall no animal is completely predictable. There are far more good ones than bad ones