I found this article quite moving. [Both links go to the article. Click to get the link itself and then click right on it.]
The basic biological model of how to be a man concentrates on bravery in the face of physical danger. It has been this way since very far back. It doesn't matter much whether you train your son to be brave or not. It is very likely that his basic drives with assert themselves and in no time, he will be interested in face-offs, showdowns, challenges and heroic victory.
If you can't find any physical danger, you can try to create some. Pick a fight with a guy. Go bear or lion hunting. Climb Mt. Everest. But as you age, punching and bashing can seem boring. Reflexes can slow down, eyesight go dim and hearing isn't so sharp. How can you continue on with body problems, especially when you have already won fights, shot lions and reached the peak of challenging mountains? What can you do with yourself if your knees go out or your back immobilizes you?
Worse, what should you do if you have no energy and steady pain, getting worse all the time? Maybe it is time to use one of your guns on yourself. Maybe the time has come.