I feel like the elephant in the room at the moment, which I'm not sure has been hit upon is obesity which I think is going to continue to affect our youth in negative ways.
Sports, activities, exercise, diet all these things are so vital for kids growing up but especially for boys. Boys need exercise, they need competitive spirit, they need an outlet for a bit of healthy aggression, they need a good, balanced diet high in protein for proper growth and development. I'm also sure there's a link between high body fat and low testosterone, which is a vital hormone in male development (which is unfortunately often associated with aggression, but also has a number of features which help with energy, mental prowess, stress management, anxiety, etc)