There are studies. There are also studies proving the opposite. This is why I'm not too worried about arguing this point forever. In fact I think I'll call this my last post in this particular thread.
Here's one excerpt I looked up, didnt remember the site, the rest I'll reference:
This is why weight training should not occur in pre pubescent athletes as it can damage the epiphysial plates or cause arrested development.
Here's another from a MD. Drgreene.com:
Injuries to growth plates can occur, but can be prevented by avoiding 'maximal lifts' - trying to lift as much as possible one time.
Here's an excerpt from WebMD.com
"Young athletes should avoid major competitive lifts," he says. "They should also be realistic about their expectations. These kids will not bulk up -- that only comes with puberty -- but they will gain strength, which is positive."
Here's one from teenhealthfx.com
A lot of what your brother is telling you is correct. There have been several studies conducted on teen weight lifting that suggest that certain types of weight lifting may damage the epiphysis, or growth plate, of your bones. There is evidence that lifting heavy weight could speed up growth plate closure, which would stunt your growth.
Seems like a few posts up I mentioned if using ultra light weight and just learning the lifts that it seemed like an ok idea to me..............