There really is no right or wrong answer to this one.
We've re-homed over 170 dogs, some young and some very old. How they are with children is entirely down to past lifestyle and how the children are towards the animal. Staffordshire Bull Terriers are, in my opinion, very loyal to their owners and although some people think they are a menace I would disagree. However, they are built like houses and can get very boisterous - this could result in injury to your children even if he is just playing. Staffy's (especially young ones) like to throw their weight around.