My brother just turned 13 in May and is entering grade 8 in September. He would like to start alittle weight lifting, right now he does push ups, sit ups, and various exercises with a medicine ball. I've heard conflicting things about children and weight lifting. I've always had it in my head that if you start weight lifting at a young age you'll "stunt" your growth or mess up your joints. However, I recently read an article about how good strength training can be for children. Except the article wasn't specific about what "strength training" included. He'd like to start curling, various dumbbell presses, bench pressing, and squats. So i'm wondering at what age he should start his free weight training. I started free weight lifting once i entered high school and i have had no problems. I've had friends tell me that you're supposed to start when your eighteen, or when you've stopped growing, are they right?

So my questions is, simply put, when is the proper age to start free weight training?

thanks for the help.