Ask yourself a simple question: What percentage of your ancestors were men? Since everybody who ever lived had a mother and a father, you might reasonably think it’s half. But recent DNA analysis indicates that we are in fact descended from about twice as many women as men. That’s because, for much of our evolutionary history, simply being a woman was almost a sure ticket to reproduction; perhaps 80 percent of all women who ever lived became mothers. But a man had to acquire power and status to attract a woman and father her children. So a much smaller share of all men—perhaps 40 percent—managed to win the race, often becoming not just serial monogamists, but serial polygamists. These Big Daddies turn up repeatedly in the family tree (meaning fewer total male ancestors). Meanwhile, the majority of men died childless, evolutionary dead ends.