Two more points:
You can add the Burgener kids to the list of above-average height individuals who lifted early on. In fact, they lifted very early and very heavy (at the national / international level in Olympic weightlifting) and have all grown to be as tall as their dad.
Also, I wanted to make something clear…there's plenty of reasons I can think of to not start a pre-teen adolescents on a weight lifting program but stunted growth is not one of them.
do you think there are certain standards that kids should meet before beginning to lifting external loads?