When I first went to highschool we had gym class and you could use the weights if you wanted. I don't think it will harm him if he keeps it light and doesn't go overboard. I wouldn't worry if I were you, he's not trying to be a competetive body-builder or anything, just make sure he doesn't go on roids

i agree with the glove missb, i dont think its anything to worry about as long as he takes it easy and doesnt just sit there for hours pumping iron

Last week I took my 13 yr old to the dr because he hurt his knee (seams to be a family thing with knee injuries) and we got to talking about health. We really got talking because he is still a veggie kid and has been now for a year and a half. One thing the dr asked him was about the amount of protein he is getting and told him that is what his muscles were made of - solid protein. She then asked him about how he worked out. He told her he took gym in school along with his everyday running around with includes alot of biking. She asked him if he did weights in guy and he said some times. She stressed nothing more then hand weights and that he should not be trying to bulk up. She then explained that you want your muscles to grow out and long but if you do lots of lifting to bulk up your muscles will grow bulky and now out and can stunt your growth. She then asked if he had seen any kids at school who were muscular but not really tall? Well that was from, they stunted their growth.

I would think that 10 lbs was ok but I think I would stop at that

Personally speaking, I'm not sure I subscribe to the stunted growth theory. If it's just because they weren't letting their muscles elongate, all that would be needed to counteract that is stretching to go along with the lifting. I was also told at a very young age (5-ish) by a Dr. how tall I would end up being. They say smoking also stunts your growth; I smoked pretty heavily all through my teens and early twenties, and still ended up being the exact same height that Dr. predicted.

I personally don't think there's anything wrong with stimulating your muscles at 13, but I also don't see any real reason to 'rush' into it that young of an age either. He'll have a whole lifetime to workout, I'd say to wait until about 16 to start. The get him involved in MMA. I'll train him.