Every few years, decades, and centuries an idea is introduced into the world that challenges the socially acceptable beliefs of the time. In the 1500s, it was Martin Luther’s 95 Thesis. In the 1800s, Charles Darwin and his theory “On the Origin of the Species.” In 2010, “Sex at Dawn” is the book that the powers-that-be do not want you to read. No other book that I have read to date so fully encapsulates the belief system that The Unbreakable Man Laws is based upon. In other words, if there was a UML Graduate course offered at Harvard (and there should be…), “Sex at Dawn” would be the required textbook.

In this interview, we speak with author Christopher Ryan, Ph.D about “Sex at Dawn” which he co-authored with his wife Cacilda Jethá, M.D. We take a brief look at open relationships, soul mates, and whether monogamy really exists and more.

As with previous UML interviews, we asked members of The Unbreakable Man Laws Fan Page questions they wanted to pose to the author. Before we jump into the interview, check out the official Sex at Dawn website, Christopher Ryan’s blog on Psychology Today, the “Sex at Dawn” Facebook Fan Page, and finally twitter @SexAtDawn.

As a special limited time offer, be sure to type a question or comment that you have for the author below for a chance to win a free copy of “Sex at Dawn.” The winner will be selected by Friday, December 3rd!

Ethan Bishop: “Sex at Dawn” suggests that women may have historically been just as open to sex as men– a lot of women seem to have a tough time believing that’s true. What accounts for this skepticism? What ways are men and women really different?

CPR: Well, let’s not underestimate the effect of several millennia of witch burnings, beheadings, beatings, humiliations, and desert stonings-to-death. That kind of campaign can really put a kink into someone’s sexual adventurousness! Women in societies that don’t cast them into the street as whores if they happen to get pregnant while single or humiliate teenage girls as “sluts” for texting a topless photo to a boyfriend seem to have much less trouble believing their female ancestors enjoyed active sex lives.

Having said that, one of the major ways men and women differ is in their erotic plasticity. This refers to our ability to adapt our eroticism to changing conditions. Women have a lot more of this sort of flexibility than men do, in general. That’s why there are so many more nominally heterosexual women who’ve had sex with other women and why basing over 95% of published sex research on American undergrads is insane. A 20 year-old woman is a far cry from an accurate representation of “female sexuality.” This also explains why almost all paraphiliacs are men. Women have illicit impulses, but in general, they can control their impulses whereas men can get stuck with very inflexible erotic associations for life.

Ethan Bishop: Your book indicates that human males are actually “well-endowed” compared to other members of the animal kingdom. Why is that?

CPR: Yes, what Dan Savage lovingly calls the “Plunger Penis” is essentially an adaptation to sperm competition. Our long, thick penises feature a flared head that, when combined with the repeated thrusting that characterizes human intercourse, creates a suction effect that serves to pull back any sperm already en route to the ovum. See our book for juicy details, if you dare.

Ethan Bishop: Does science hold up to the theory of “soul mates?” How do you think this idea came about?

CPR: Science doesn’t say much about it, but it stands to reason that with our highly social nature and advanced intelligence (at least compared to other animals), our ancestors would have had very intimate, spiritually-charged relationships. Science tends to focus on the brain states associated with infatuation (what anthropologist Helen Fisher calls “falling in love”). The sort of spiritual union that is implied by “soul mates” is, I think, beyond the explanatory capabilities of science.That soul-mateship would necessarily imply sexual monogamy is where we differ with the conventional wisdom. It seems to me (and a lot of other people) that you’d want your soul mate to have as much pleasure and intimacy as possible in life unless something cultural interfered with that impulse.

Ethan Bishop: Why are women louder during sex than men? Are they all “faking” or is there some evolutionary reason?

CPR: Scientists refer to this as female copulatory vocalization. Interestingly, it seems to occur mostly in primate species where female promiscuity (and thus sperm competition) is common. Some women may fake it, as it’s a good way to provoke orgasm (and ego inflation) in men. But clearly, a lot of the screaming and moaning is involuntary and thus serves as yet another indicator of our orgiastic origins.

Ethan Bishop: Is monogamy a social construct imposed by government in order to maintain order and property rights? For instance, who owns Property A and whose responsibility is Child B?

CPR: That’s essentially what we argue in Sex at Dawn—and what Engels and others argued 150 years ago. The data indicate that monogamy probably arose around the same time our ancestors started worrying about property, and thus, paternity. Once property entered the picture, a man wanted to pass his accumulated resources along to his sons, not someone else’s sons. The only way to assure that they WERE his sons was to control his wife’s sexual behavior. So we see indications of how obsession with property overlaps obsession with female fidelity: “Thou shalt not covet thy neighbor’s wife. Nor his house. Nor his maidservant. Nor his manservant. Nor his ox. Nor his she-ass.” You know, this isn’t about sex, really; it’s about property. Thou shalt not covet thy (male) neighbor’s STUFF—and that stuff includes “his” woman. Throughout history, we see that virginity and female fidelity are especially important among the upper classes—who have the property to worry about.

Ethan Bishop: How should “Sex at Dawn” change the personal relationships we have?

CPR: There are very few “shoulds” in Sex at Dawn. Our book isn’t an indictment of monogamy or a call to open relationships. We say (and strongly believe) that monogamy can actually be a very honorable option. But it’s like vegetarianism. Just because you’ve decided to be a vegetarian, don’t expect bacon to stop smelling good. And maybe you can find a way to make exceptions for the occasional pepperoni pizza and still consider yourself (and your partner) essentially a vegetarian. All we really advocate in the book is tolerance, communication, and a more realistic approach to these issues that incorporates a more accurate sense of what kind of creature Homo sapiens really is.