Girly men
Cracked answers Karen De Coster’s implied question

Historically women were attracted to strapping, virile men who would pass on their bulging, hairy-chested, muscular genes to their children. Obviously the point was to ensure that the resulting offspring would be strong enough to survive all the horrifying claptrap that goes on in the forest at night.

Thanks to some hormone magic, this tends to change after the woman is pregnant.

But when on the pill, a woman’s body thinks she is pregnant all the time.