Will weight lifting, strength training, etc, stunt my or my child's growth?
If you (or your child) aren't sprouting up as quickly as the other kids and you've been lifting weights, it's easy to resort to believing the old wives' tale that you're short because of the weight training. We may never know how this rumor began propagating, but there is certainly little (if any) evidence to support it. In fact, there is evidence suggesting the opposite.
Why do people think strength training may stunt one's growth? That's really a good question. I suppose people imagine that, much like the foot-binding practices of ancient Japan, holding weights (on the back while squatting, for instance) might counteract the body's growth, perhaps by damaging growth plate closures and causing premature termination of growth. This is a conclusion that actually makes some sense. With the addition of that medical mumbo jumbo about growth plates, it might actually pass off as a valid argument. Luckily, there is research indicating otherwise, but common sense would also indicate otherwise: if increased spinal load were the cause of stunted growth, children who run, walk, jump, climb, or even stand upright should be shorter than average. Kids who play basketball would all end up being shorter. Kids who play football crash into each other at high frequency -- these children should also be shorter.
As it turns out, there are very few sports found to have possible impact (no pun intended) on height, and the cause for their effects come as no surprise. Two such sports are gymnastics and wrestling. Athletes that perform in these sports at a high level undergo extreme physical conditioning. Some research suggests that their bodies may not be able to grow to full height. One study found that "prolonged inhibition of the hypothalamic-pituitary-gonadal axis by exercise, together with or because of the metabolic effects of dieting is responsible for [effects on growth]." (source) However, there is a lot research suggesting that reaching full adult height, even for athletes in these sports, is the norm.
That said, malnourishment and extreme physical stress can definitely cause growth to stunt. If the body isn't given adequate time and conditions to recuperate, it would make sense that growth would suffer. Not getting enough sleep, eating poorly, and being exposed to toxins such as cigarette smoke or steroids can stunt growth. However, consider the following results from the research:
"Experimental training protocols with weights and resistance machines and with supervision and low instructor/participant ratios are relatively safe and do not negatively impact growth and maturation of pre- and early-pubertal youth." http://www.ncbi.nlm.nih.gov/m/pubmed/17119361
"Numerous studies have demonstrated that with appropriate supervision and precautions, resistance training can be safe and effective for children and adolescents. " "[Resistance training had] no detrimental effect on linear growth."
Hopefully the research speak for itself. It seems that for a normal, healthy kid, worrying about it is probably wasted energy.