A new book titled “Sex at Dawn: The Prehistoric Origins of Modern Sexuality” seeks to prove the thesis that human biology and evolution was designed to facilitate multiple sexual partners. The author of this book, Christopher Ryan, traces the origins of this work back to his doctoral thesis on the subject. He selected this arena of study during the height of the Clinton/Lewinsky scandal, and he sought to identify the origins of the urge to sleep around which drives many to take otherwise unthinkable risks. Since the time of Lewinsky, myriad men including Tiger Woods, John Edwards and Elliot Spitzer have borne out this theory, and Ryan asserts that society’s expectation that you should be with one partner for 50 years goes against human nature.

This book documents that adultery has been rampant in every human culture ever studied, and that a man’s inner urge to spread his seed far and wide is as compelling as the urge to eat or breath. The author further claims that evolution has also prompted women to desire to spread their risk and seek genes from multiple men so as to ensure at least one healthy child. The author strives to bifurcate love versus sex — he claims that love is different from lust and that family unit relationships based upon love are preferred. However, he also asserts that occasional random sex outside of the relationship does not indicate any less love for your partner — an argument many guys would be hard pressed to make to their wives. However, if you wanna make a go at that, you can use this book as a reference when trying to convince her it is ok for you to chase an occasional waitress or barrista.

With the amount of casual sex that goes on these days, you would be wise to conclude that both men and women feel pretty good about it. Surprisingly, you would be wrong, according to a study published in the journal human nature. Researchers from Durham University in the United Kingdom surveyed thousands of people who had casual sex encounters and got answers about their feelings on the incidents. There were some interesting results.

The researchers theorized that if there are evolutionary benefits to casual sex, such as to spread the proverbial seed for guys, then positive feelings about the practice would develop to reinforce its practice in society and pass down the genes. For women, it is less clear what the evolutionary reason, but it could be to draw from a larger number of quality partners to increase the chance of one of them producing offspring with quality genes. These types of concepts were looked at going in.

The results showed that men felt positive about causal sex 80% of the time, while women felt positive about it only 54% of the time. Men felt more sexually satisfied and confident about the experience and were less concerned if others found out about it. Women reported feeling used and unappreciated, and were concerned that others finding out could damage their reputation. Also, women were not as sexually satisfied and perhaps surprisingly, did not feel any expectation that casual sex would lead to a longer term relationship.

Women clearly had much more negative feelings about casual sex than guys according to the study. The bottom line, however, is that quite a bit of casual sex continues to go on and shows no signs of stopping. The question, then, is what drives women to participate if their feelings about the experience are lukewarm?