An "article" I found a long time ago which I saved on my computer:
"Many times we hear people say that young children should not perform heavy weight training in the fact that it stunt's their growth. Many scientist have researched this and provided evidence that this theory is not true. The Soviet Union published a book known as 'The School of Height' debunking the myths that children should not do heavy weight training. Great Britain published a journal study supporting this, outlining tests they performed on young powerlifters showing they had better bone density and their bones where much more durable than that of children not subjected to heavy weight training or any other form of impact loading.
It is also relevant to note that athletes subjected to heavy loading and resistance are relatively free from osteoarthritis in old age and the subjects that were not exposed to heavy loading and resistance show a much greater incidence of osteoarthritis and cartilage fibrillation. Furthermore, there has also never been a documented case that claims weightlifting has stunted the growth of a child.
What many people don't understand is everyday physical education classes and activies that have nothing to do with moving maximum weight is far more dangerous and hazardous to your child than lifting weights. The soft tissue and connective tissue injury rate is rather low in competitive weightlifting compared to that in contact sports such as football, rugby and soccer.
From 1977-1988 permanent spinal injuries in high school football players reached 96 and 15 in college during that time.
From 1984 to 1988 over 15 high school football players ended up brain dead and 3 college football players ended up brain dead.
Even martial art sports have more spinal injuries then Olympic Weightlifting who of which has recorded ZERO!
In force plate test have shown that jumping is actually six times more stressful on the knee and connective tissue then squatting with heavy weight. The spine actually will obsorb more shock from jumping then placing a heavy load on shoulders where the body supports it.
Conclusion:
Weightlifting is safe and will NOT stunt your growth. You have a better chance of having brain damage or some life time disability from playing your every day sports you play in PE class than lifting heavy loads."