Eve summary

What do you think of when you hear the word pregnancy? A magical, almost transcendent experience of creating life? Or have you actually been pregnant? 

Far from the idealized, cheerful version that’s sold to us, pregnancy is a biological battle. Human reproduction intrinsically pits the mother's health against the demands of the fetus. 

Have you ever wondered how humans managed to spread across the globe and become the dominant species? After all, we’re not the fastest or strongest, we reproduce pretty slowly, and our children are dependent on us for a long time.

One common answer is that men started to wield tools, swinging hammers and throwing spears. But perhaps the revolution came with an invention that couldn’t be preserved as neat archeological artifacts – an invention for, and by, women. 

What makes women different from men? This question has occupied scientists and philosophers for ages. Often, the answer comes back to hormones, emotions, childbearing – often framed as differences in the “female brain.” But what does neuroscience really tell us about those differences?As it turns out, not as much as you might think. Despite age-old stereotypes of the moody, math-challenged “weaker sex,” adult men’s and women’s brains are remarkably similar in structure and function. While boys and men tend to do slightly better on tests that require spatial reasoning, girls and women do better on tests related to language skills.

But overall, sex differences in aptitude and behavior have more to do with socialization than with hardwired biology. Take intelligence. Up until adolescence, boys’ and girls’ IQ test performance is pretty much the same. Even differences in average math scores narrow when controlled for economic status. So intelligence is not so much inborn as cultivated through opportunity and experience. 

One real, undeniable difference between the sexes is that women live longer than men – over five years, on average. The reason why may have to do with something our society prefers not to discuss: menopause.

From an evolutionary perspective, menopause is a mystery. Most species keep reproducing until they die to pass on their genes. But human females stop being fertile often decades before the end, living up to a third of their lives after menopause. Why? 

What truly separates humans from other intelligent, social species like chimps? It’s not big brains or opposable thumbs. It’s our intricate, long-lasting, and emotionally intense bonds, including with non-relatives. We don’t just reproduce, we “make love.” In the animal kingdom, this type of romantic love is unmatched. But how did it evolve?

The mainstream scientific view is that early human females made a sort of “devil’s bargain.” Initially, they lived in promiscuous matriarchal groups. But as giving birth grew more challenging, they needed more resources to successfully raise offspring. So they started offering individual males exclusive sexual access and certain paternity of their children, in exchange for food and protection. These individualized bonds added to the assistance offered by the larger female collective.