My nephew, age 14, wants to go to the gym. The most important step is already done - he bought some protein powder (careful, irony). However, my sister is opposed to that idea since in her opinion, 14 years is way too young to start lifting weights.
And indeed, a quick google search reveals that the public opinion in the western hemisphere mostly seems to agree with her. It is dangerous, the body is still in the process of growing, the back is too tender,...
If you take a look at ex-soviet countries however, it appears to be quite different. The average Boris Sheiko or Ivan Abadijev trainee started training before or during puberty. Kids seem to be sent to olympic weightlifting training or powerlifting training there like they're sent to soccer in my country (Germany). It's hardly a coincidence that podium spots at IPF Worlds are dominated by russian, bulgarian and ukrainian flags.
The assumption that you have to be an adult to participate in weight training doesn't check out on an intuitive level for me either: The younger a body is, the higher are his capabilities to recover from injury, right? That is, if the injury occured to begin with, because it's approximately 5.000 times more likely to get injured while playing soccer.
Personally I think the only real danger for my nephew (apart from malnutrition due to eating nothing but protein shakes) stems from juvenlie recklessness, like attempting to lift an absolutely inappropriate weight, but that can easily be mitigated by proper supervision and training.
So, my question: Is there an accepted minimum age for general weight training? Has this topic been scientifically researched, and what are the actual dangers for people below that age?