The TODAY had an excellent segment on children bodybuilding. It's all about balance. You do not want them obsessed with their bodies early on, and heavy weights can injure their growing tissues. However, light weights with many repetitions can condition them for life and sports and going to the gym regularly if they choose starting at 18 years old. I advocate more walking, calisthenics and sports for children.
The psychologists's and doctor's comments at the end are great.
My new fitness book Pocket Guide to Fitness Edition II is out now!