Sex at Dawn by Christopher Ryan and Cacilda Jethá — book cover
Monogamous relationships · Sexual behavior · Sexual behavior in animals

Sex at Dawn by Christopher Ryan and Cacilda Jethá — Summary, Key Ideas & Quotes

2010400 pages3-min Big ideas4.7 (6)
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What is Sex at Dawn about?

"A controversial, idea-driven book that challenges everything you know about sex, marriage, family, and society"--Provided by publisher. Since Darwin's day, we've been told that sexual monogamy comes naturally to our species. But this narrative is collapsing. Here, renegade thinkers Christopher Ryan and Cacilda Jethá, while debunking almost everything we "know" about sex, offer a bold alternative explanation. Ryan and Jethá's central contention is that human beings evolved in egalitarian groups that shared food, child care, and, often, sexual partners. Weaving together convergent, frequently overlooked evidence from anthropology, archaeology, primatology, anatomy, and psychosexuality, the authors show how far from human nature monogamy really is. With intelligence, humor, and wonder, Ryan and Jethá show how our promiscuous past haunts our struggles over monogamy, sexual orientation, and family dynamics. Human beings everywhere and in every era have confronted the same familiar, intimate situations in surprisingly different ways. The authors expose the ancient roots of human sexuality while pointing toward a more optimistic future illuminated by our innate capacities for love, cooperation, and generosity.--From publisher description.

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Illustration for Sex at Dawn
The Myth of Natural Monogamy

Ryan and Jethá argue that the commonly held belief in natural human monogamy is a cultural construct rather than a biological imperative. Drawing on evidence from anthropology and primatology, they suggest that pre-agricultural humans lived in egalitarian groups where sexual exclusivity was rare. The book contends that the nuclear family and monogamous pair-bonding are relatively recent developments, shaped by the advent of agriculture, property, and inheritance.

Evidence from Our Primate Relatives

The authors compare human sexuality to that of our closest primate relatives, particularly bonobos and chimpanzees. These species exhibit high levels of promiscuity and social sexual behavior, which serve to strengthen group bonds and reduce conflict. Sex at Dawn uses these comparisons to argue that human sexual behavior is more flexible and communal than the strict monogamy seen in some other animals.

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Open Library
4.7 / 5
6 ratings
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6 key ideas, distilled
  1. 1The Myth of Natural Monogamy
  2. 2Evidence from Our Primate Relatives
  3. 3The Impact of Agriculture and Property
  4. 4Rethinking Jealousy and Infidelity
  5. 5Diversity in Human Sexual Expression

Popular quotes from Sex at Dawn

Perhaps our culture’s greatest lie is the myth of monogamy.
We are the descendants of hypersexual ancestors.

Frequently asked

"A controversial, idea-driven book that challenges everything you know about sex, marriage, family, and society"--Provided by publisher. Since Darwin's day, we've been told that sexual monogamy comes naturally to our species. But this narrative is collapsing. Here, renegade thinkers Christopher Ryan and Cacilda Jethá, while debunking almost everything we "know" about sex, offer a bold alternati