If you are like me, you’ve probably been taught that fulfillment in one’s personal life means connecting with someone who you love and loves you back, marrying them and creating a stable and happy family. It seems so simple and natural, something inherently human and common to all of us.

But is it?

Sex at Dawn authors Christopher Ryan and Cacilda Jetha delve into our ancestors love lives and sexual relationships in a time when monogamy didn’t exist yet as a generalized way of life, and through their findings put forward a thought provoking theory in regards to our sex lives and relationships.

What you can learn from this book:

  • Why monogamy is unnatural for humans
  • Why women moan during sex
  • Why men and women have a different path to orgasm


How many people have you had sex with? Depending on the number, you may think you are a promiscuous person, but you probably aren’t able to compete with our ancestors.

In prehistoric tribal societies, sex wasn’t viewed as an expression of love, but rather as a resource and all resources in such societies are pooled together and common for everyone, including sex.  Basically, everybody fooled around with everybody else, creating a pleasant and relaxing atmosphere within the tribe.

Such societies faded away in the end.  Over time, religious and social norms imposed constraints on our sexual and emotional lives, creating the current monogamous lifestyle. But some societies remembered the old way of doing things. The Romans for example practiced monogamy, but nevertheless considered it unnatural and as a consequence it was customary for a bride to engage in an orgy just before the wedding took place, so that she may appease Mother Nature for the unnatural life she was about to embark on.

But how and why did our relationships and sex lives change so much? In a word, agriculture. By it’s very nature, agriculture requires a sense of property. My land, your land; my animals, your animals. Property was kept in the family by way of inheritance, so it was important for a farmer to be sure that the children he was raising were his. As a result, women were prevented from having sex with other men through shaming, punishment, exile and other such means. The most effective method of enforcing sexual monogamy was marriage, which often gave the husband extensive rights he could use to keep a woman in check.

Because of this strict control of female sexuality, a belief started to develop that women have a lower sexual drive than men. This claim has been proven false through extensive research, but it is true that women try to hide their sexual desires, in an effort to conform to social expectations and moral norms.

But our polygamous nature didn’t only influence society, it influenced the evolution of our bodies and sexual behaviors. The human penis for instance is the biggest in the animal kingdom relative to the size of our bodies. Its size and shape, together with the thrusting motion during sex, is designed to effectively pump out the sperm of other men, thus increasing ones own chances of impregnating the woman.

And physical aspects don’t stop there, the difference in height between men and women owes its existence to our promiscuous tendencies. Women preferred taller men since they were viewed as stronger and healthier than shorter ones, however men didn’t have such a sexual preferences when it came to women, so height differences emerged between the genders. This is a frequent behavior in polygamous animals, but not in monogamous ones. Animals that mate for life, such as gibbons, tend to have similar or identical physical dimensions.

Women have also evolved their own traits. Have you ever wondered why some of them are loud enough during sex that they can be heard from afar? In prehistoric times, such noises were meant to signal to other males that she was having sex, functioning like an invitation for them to try their luck, thus encouraging sperm competition between the men.

This evolutionary perspective on human sex and reproduction also explains why men and women reach and experience an orgasm in such different ways. Women need more time to reach an orgasm than men do, but on the flip side they can also have multiple ones. This suggests that they engaged in sex for longer periods of time and with multiple men, one after another, achieving multiple orgasms in this interval. Men on the other hand orgasm quicker and afterwards feel sleepy. This resting period offered the chance for another man to have sex with the woman, once again encouraging sperm competition.

But surely, things have changed over time. Modern relationships are built on love and respect, and sex with that one special person will always be great! At least that’s what we are told.

Unfortunately, things don’t quite work out like that. Ultimately we are still biologically programmed to seek sex with multiple partners, even though we put in serious effort into being monogamous. This conflict between our biological selves and our cultural upbringing can be a profound source of unhappiness and inner tension in our lives. In the end, monogamy is something that we must learn how to master.


An 900 word article can only say so much about a book, if you want the whole story, you can order it here from Bookdepository and benefit from it’s free shipping policy.

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EDIT: We have been called out for the misleading title, so we modified it to better emphasize that this is a theory and not scientific mainstream. All of the information is taken straight from the book however and we just present the author’s findings.

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