[GraniteStateConservative]

But if you confine yourself to things normally regarded as risky, such as fighting or promiscuity, the consequences are less clear. There are times and places where being timid is a good survival strategy, and times and places where being bold is necessary.

Promiscuity is a tougher nut because the risky act involves attempted procreation, even though STDs could kill the person or render him incapable of fathering children later.

Fighting is very risky in human populations. Objectively bad for procreation chances. If all of the fit men go off and die in battle, the unfit men left behind will procreate with the young women at home because that's just what nature has men and women programmed to do. Fighting in the wild is different, but a weaker human can pull out a gun and easily slay a brawny Goliath, or a gang of weaker unfit people can overpower the single Goliath, or any other crazy thing could happen. It's really stupid for even a fit Goliath to start fights. Hell, Goliath could survive a fight, but get kicked in the balls repeatedly during the melee, rendering him impotent or sterile.

[js1138]

Fighting is very risky in human populations. Objectively bad for procreation chances.

Then explain why somthing like 16 million men carry Ghengis Kahn's Y chromosome.

[ColdWater]

If all of the fit men go off and die in battle,

Uh, those fit men spread quite a few genes around as they go off to battle.