Throughout history, boys have undergone rites of passage into manhood that imbued them with knowledge and skills for the real world. Many of these experiences prepared them for combat or a battle for scarce resources. Often it involved testing themselves against their peers in speed, strength, organizational planning, strategic knowledge, developing purpose, the social skills of teamwork, personal integrity or trustworthiness and courage. The stature acquired in these social tests contributed to winning "street cred" and women's favour so they could gain a mate to propagate and ensure their clans continuation and survival.
It is now clear from DNA mapping that we are genetically descended from twice as many women than men. This single under appreciated fact confirms that while 80% of women mated, they did so with only 40% of the male population. These reproductive odds produced well defined behavioural and personality differences. For women the odds of reproducing were pretty good. Taking chances fighting or exploring strange lands would be stupid, the optimal thing to do is go along with the crowd, be nice, play it safe. The odds are good that men will come along and offer sex. All women had to do was select the most promising hunter and mate.1
But for Men it was radically different. They had to compete to win the evolutionary sweepstakes and 60% of them failed. So it was necessary to take chances, try new things, be creative, explore other possibilities. Sailing off into the unknown may be risky but you might strike it rich and have a better chance at mating. The evolutionary odds of success in staying at home and going along certainly weren't great. Risk taking behaviour mattered even from the aspect of sex drive as a man who said "not tonight dear" may have missed his only chance at evolutionary success.
So basically we’re behaviourally descended from women who played it safe and men who took risks. In subjective terms it means that for women, being lovable was the key to attracting the best mate. For men however, it was more a matter of beating out lots of other men even to have a chance for a mate. Men are hardwired to take risks and compete with each other whereas women are predisposed to play it safe and concentrate on suitable mate selection.
1) The bulk of this Evolutionary Psychology is taken from address of Dr. Roy F. BAUMEISTER "Is There Anything Good About Men?" American Psychological Association Address, June 2007.