Sex at Dawn

Exploring the evolutionary origins of modern sexuality

FAQ About Sex at Dawn (Last in Series)

Ask a good question, win a great book!

In celebration of the publication of Sex at Dawn this week, I'm running a series of FAQ that often come up when we're talking about the book, whether at cocktail parties or conferences. You can see the whole list at our website here. Also at our site, you'll see a form for contacting us. If you're interested in the issues we cover in the book, and have a nagging question you'd like to see us take a shot at answering, let us know. We'll be choosing the five most interesting questions to answer in future blog posts here. If we choose your question, we'll send you a free copy of Sex at Dawn. Looking forward to your questions and comments.

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1. If monogamy isn’t natural, why have I read that marriage is universal among all human societies?

Many anthropologists who have argued that “marriage” is universal haven’t agreed on a clear definition of what they mean by the word. In Sex at Dawn, we discuss societies where so-called “married couples” don’t expect sexual exclusivity, exchanges of property, cohabitation, any difficulty in ending the union, a relationship between extended families, or even a hint of paternal responsibility. Yet anthropologists still insist on calling these relationships “marriage.”

2. If your thesis is correct, then why do almost all industrialized societies prohibit—at least officially—infidelity?

It’s almost impossible for most of us to appreciate how radically different the social world of our ancestors was from what we experience today. Anthropologists agree that pre-agricultural societies almost universally share a passionate commitment to so-called “fierce egalitarianism.” Because they are nomadic, such people accumulate as little personal property as possible, thus resulting in cultures organized around sharing. Food, shelter, child-care, protection from predators . . . all are scrupulously shared.

With the advent of agriculture just 10,000 years ago (less than 1/20th of our existence as anatomically modern Homo sapiens), personal property became all-important. Families accumulated land, buildings, status, and wealth that they wanted to keep in the family. The only way a man could ensure his paternity was through strictly controlling his wife’s (or wives’) sexual behavior. Thus, female infidelity has been ruthlessly punished for millennia. Most evolutionary psychologists assert that male obsession with controlling female sexual behavior is intrinsic to human nature, but the evidence we present in Sex at Dawn shows it to be a response to economic conditions that arose with farming.

3. When I hear my (heterosexual) neighbors having sex, why is it almost always the woman who is loudest?

Believe it or not, there are scientists who follow primates through the jungle with microphones, collecting data on what’s called “female copulatory vocalization.” What they’ve found is that the females of the more promiscuous species tend to have the loudest, most complex vocalizations. Don’t tell the neighbors!

4. Does human nature lead to war or peace, selfishness or generosity?

Asked this way, this question will never be answered. The nature of human nature is changeability. Is the natural state of H2O solid, liquid, or gas? Context is crucial.

5. Aren’t we much healthier than our ancestors were? After all, they only lived into their thirties.

The widely-accepted idea that a thirty five year-old stone age person was “old” is simply untrue. In Sex at Dawn we show that our prehistoric ancestors typically lived into their fifties, sixties, and even seventies.



"Sex At Dawn is the single most important book about human sexuality since Alfred Kinsey unleashed Sexual Behavior in the Human Male on the American public in 1948. Want to understand why men married to supermodels cheat? Why so many marriages are sexless? Why paternity tests often reveal that the guy whose name is on the birth certificate isn’t the kid’s biological father? Go and buy a copy of Sex At Dawn. Anyone who’s ever struggled with monogamy—which, if people were honest, would be everyone—needs to read this book. Go get your hands on a copy now."

— Dan Savage, author of the internationally syndicated sex-advice column “Savage Love” and of The Commitment: Love, Sex, Marriage, and My Family.


For more information, visit

Click here for a recent review of the book, or here for an interview at

Christopher Ryan, Ph.D., is co-author of Sex at Dawn: The Prehistoric Origins of Modern Sexuality (HarperCollins 2010).


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