I guess I can't really see any problem with it, at worst they are nothing more than carbonated bevorages with extra caffine in them, over tha long term they aren't goign to cause major damage. Its basically equivilent to drinking about 4 cups of coffee. One might argue that the "comming down" part of the experience could produce unwanted side effects. But honestly these drinks are no wrose for kids than Soda especailly Mountain Dew which has enormous amounts of sugar and caffine in it. I guess in conclusion, used in moderation I don't think they are that harmful.