Why do women have sex?

For the same reasons men do, explain the authors of a groundbreaking new book that looks deep inside female desire

Published October 5, 2009 7:07AM (EDT)

Women just don't think about sex all that much. They have sexual fantasies only twice a month. Sometimes, they have sex simply out of a sense of duty.

Disagree with any of that? Find those sweeping statements enraging? So did I, at times, while reading "Why Women Have Sex," a groundbreaking new book by clinical psychologist Cindy M. Meston and evolutionary psychologist David M. Buss, two researchers at the University of Texas at Austin who have conducted a wide-ranging survey into the dark corners of our sexual subconscious. Still, I also found myself nodding vigorously and letting out crescendoed "mhm's" as I read through the study of more than 1,000 women.

The standout finding, one that feels decades overdue, is that women have sex not for babies or emotional intimacy but rather for reasons of attraction and pleasure, because "it feels good." In other words: the same reasons men have sex. And men aren't the only sexual conquistadors: Women enjoy the thrill of the chase and can be just as viciously competitive with same-sex rivals. And, speaking of competition, the book posits a theory of "mate copying," in which women are drawn to men who come pre-approved by other women. (Indeed, who hasn't experienced a sudden tingle of attraction upon seeing another woman go after a man who was previously uninteresting?) Plenty of fascinating generalizations are made, but the book's real takeaway is that there is tremendous individual variety among women.

The thrill of recognition, of having my personal experiences validated -- by science! -- was often crushed, though, by the evolutionary psychological theories that frame the text. Yes, I have lusted after flings with square-jawed macho men and landed sensitive, committed types for relationships -- but is that really because on a subterranean level I want a lothario's great genes and to pair-bond with a sensitive type who will be faithful and help take care of the kids (even if they aren't actually his)? I wanted the book to hold up a mirror to my sexual psyche, but at times the reflection showed too much cavewoman for comfort. (Women who dig other women may find themselves even more annoyed. While the book repeatedly touches on same-sex attraction, many are likely to feel left out of the larger evolutionary thrust of the book.)

But the reality of human sexuality is often uncomfortable. The good news is that Meston and Buss are not biological determinists; they believe that "evolved psychological adaptations are not inflexible instincts."

Salon spoke with Meston and Buss by phone about rape fantasies, the purpose of the female orgasm and why all the good guys really might all be taken.

So why does the question "Why do women have sex?" warrant a book-length answer? Why isn't it as simple as: It feels good, or women want babies?

Cindy Meston: The focus in the past has been on understanding what people are doing sexually and how frequently they are doing it -- the Kinsey report being the ultimate in that regard, with its survey of 18,000 Americans -- but very few people are talking about why they're doing it. If we're really to understand female sexual behavior, we have to understand the underlying motivation. I'll give one example of why: Giving a condom to a woman who is engaging in high-risk sexual behavior isn't going to help in the least if her underlying motivation is to punish herself. You have to understand what motivates behavior if you want to change it.

What do most women find physically attractive in a partner?

Meston: Women like tall men, v-shaped torsos and deep voices -- all of these attributes are symbolic of high testosterone. They give symbols of status, power, earning potential and strength. From an evolutionary perspective, those are probably remains of needing a guy who could physically protect you and could go out and hunt down the antelope.

In addition, there are love maps. Every woman has her own ideal of what she finds attractive. Some women like short men, some like curly blonds, some like dark bearded types. You often hear a woman say, "He's not my type, but he's your type." Love maps develop very early on when we're children. We develop a template of what we find attractive based on our experiences with people in the past.

How do we explain same-sex attraction, then?

David Buss: That's a mystery that nobody really has figured out yet. From an evolutionary perspective you would think that evolution by selection would pretty strongly channel sexual orientation into heterosexual orientation, and by and large it does. But clearly there is a significant minority who develop same-sex sexual orientation. My guess is that ultimately it's going to be something that is multiply determined. If there was one big cause we'd already know it, but we don't.

How do you explain the female orgasm? What evolutionary purpose does it serve?

Meston: Most of the evolutionary theories for women having an orgasm have been disproved. Initially, it was thought it triggered ovulation, which of course it doesn't. Then it was thought that orgasm helped pull more sperm in and increased the chances of getting pregnant. There is still some evidence that through the process of orgasm and the contractions of the uterus some of the crappier sperm die off so that the healthier sperm are more likely to make it to the egg.

It could be that there is a psychological purpose in the sense that if orgasm feels good it's going to make women want to have sex more, and the more they have sex, the more likely they're going to get pregnant.

A question that is probably on many women's minds is, "Why aren't they easier to come by?"

Meston: Well, the good news on that is that, with the exception of certain medical diseases -- like diabetes, certain spinal cord injuries or prescription drugs like antidepressants -- there is no evidence whatsoever that some women are incapable of having an orgasm. It's simply a matter of not having learned how. Also, twice as many women are able to have an orgasm through masturbation than with a partner -- well, why is that? Because a woman knows where to touch that feels good, and she may not be willing to communicate that to her partner -- or maybe her partner isn't willing to listen.

A lot of times women are anxious during sex. They're more worried about whether their butt looks nice than what sex feels like. It's not very sexually arousing to be worried about whether your thighs are flabby or whether your partner is looking at your droopy left breast. When you feel crappy about your body it's hard to feel sexual.

What about pornography. Why is it so much more popular with men?

Meston: Men are just much more easily turned on by physical cues. Many women will find sexual films arousing, but context is so much more important for women than men.

What about the ever-controversial rape fantasy?

Meston: Usually when the research is done on the rape fantasy, it doesn't involve a lot of violence. There is force involved, the man is taking the woman, and there is arousal in that -- but there isn't a real threat for their life. It's similar to these romance novels where the guy is so overtaken by the woman and wants her so much that he just takes her. There is some amount of abandonment and letting go on the woman's part. There is something arousing about the submission and being so desired that the guy can't help himself.

Now, a true rape fantasy -- where a woman is taken in a dark alley, beaten and raped -- is much more rare. Some women do have those, but they are not sexually arousing. They are terrorizing. Often it is women who have actually been sexually assaulted who experience these fantasies. Some people believe those types of true rape fantasies serve the purpose of making women more vigilant and more cautious

Pickup artists have created how-to guides to scoring with women by creatively reinterpreting the same kind of research and evolutionary analysis that is found in your book. What do you make of their tips?

Buss: Some of them make good evolutionary sense, and some of them seem kind of wacky. Some of the techniques they use involve trying to hijack women’s desire for men who are high in status. They’ll do things like make themselves the center of attention. People are very sensitive to status and one of those most important things to status is commanding attention. So, they teach you how to become the center of attention.

Another tactic that they use with very attractive women is what they call the "neg," which is the opposite of a compliment. It’s a signal that they’re not desperate, that they are high in mate value, and it also possibly has the effect of lowering the woman’s self-perception of her own desirability.

On a similar note, studies have shown that women tend to prefer slightly less masculine men for long-term partnerships and tend toward macho types for casual sex. Why is that?

Buss: There is a definite shift between short-term and long-term mating. So for long-term relationships, women are going for guys who are good dads, based on cues like niceness, kindness and cooperativeness. In short-term mates, that's obviously not as important.

The masculine qualities are linked with testosterone production, which is viewed as an honest health indicator. It’s kind of a paradox: Testosterone compromises the immune system, so only men who have high-functioning immune systems can afford to crank out a lot of testosterone, whereas those men who aren’t as healthy can’t afford to. The testosterone is what produces those masculine features – the square jaw, the heavier brow region. It lowers the voice and produces that muscular build.

That relates to the "sexy son" theory. Can you explain that?

Buss: The logic is that if there are genes associated with desirability to women, then women who mate with those guys will have sons in the next generation who are highly desirable to women. And so they will be rewarded with more sons who will produce more grandchildren. None of this is at all consciously registered. Women don’t look at a guy and think about his genes. It just means they find some guys more attractive than others.

Another theory discussed in the book is "mate poaching." 

Buss: Men and women who are high in mate value tend to get snapped up. Not always, but they are often in relationships. What that means is that you often hear women complain there are no eligible men -- all the men are either married, permanent bachelors or gay. There is some truth to that, in that guys who are commitment-oriented tend to get in relationships. It really does shrink the pool of desirable men who are out there for single women. What that means is that the truly desirable people, or a fraction of them, are already in mating relationships. So, mate poaching becomes an option.

How do we explain the stud-slut double standard? What kind of evolutionary basis is behind that?

Buss: The short-term, long-term distinction is critical. All I can offer is a speculation: One of the key adaptive problems that men have to solve in picking a long-term mate is assuring that they’re the father. It's the paternity certainty problem. This stems from the fact of our reproductive biology. Fertilization occurs internally in women and not men. Maternity is always 100 percent certain, and paternity is always less than 100 percent certain. Men look for cues to sexual fidelity with long-term mates.

The number of premarital sex partners is a good predictor of infidelity post-marriage. That applies for both men and women. The higher the number before marriage, the higher the probability that there’s going to be an infidelity in the marriage. Ultimately, I think that’s part of the reason for that double standard.

It seems like there is a fundamental conflict between these evolutionary drives and where we currently are socially and politically. In a way, it feels like we're trying to fight our own nature.

Buss: It may be an evolutionary lag. Certain mate preference may be no longer necessary in the modern environment -- much like we have the taste preferences for sugar and fat, which currently lead to obesity and Type 2 diabetes. It might be that some of these desires or mate preferences are outdated, but we’re kind of stuck with them for the moment because the evolutionary process is very slow. Sometimes people successfully fight it. They go on a diet and resist chowing down on the high-fat stuff.

Why do we see sex drive disparities between couples? It would seem that similar drives would serve a greater evolutionary purpose.

Buss: Basically, it stems from the cost associated with sex or the cost associated with making bad sexual decisions. For men the costs historically have been relatively trivial. If a man and woman hook up and wake up the next morning and realize it was a mistake, for the man it's no big deal. If a woman got pregnant that could be very costly for her. If the guy had poor genes she’d be stuck with those, and if he’s not around to invest that’s another problem. There’s a big cost disparity between making sexual mistakes about who you have sex with. Men who were sexually successful with women simply reproduced more than men who had sex with fewer women.

What do you make of hookup culture, then? How do we explain young men and women who are similarly driven to sleep around?

Buss: I think it’s an interesting phenomenon. I would be surprised if it were actually similarly driven, though. I know it’s become more socially acceptable to do that. Women do benefit from it, if only in the form of emotional benefits, getting sexual needs satisfied with a friend she can trust. It’s also my hunch that women are probably gaining other sorts of benefits -- in a pinch she can probably call the guy if she needs him for something. Do men and women equally want the no-strings-attached hookups? I would really doubt it.

The immediate response of any woman who doesn’t fall comfortably within that category will be to say, “But that’s not true for me.”

Buss: There’s no doubt. And there are tremendous individual differences among women, and women who are truly into short-term mating. Why these individual differences exist, I’m not sure. What I’m referring to are overall sex differences and within each sex you do have tremendous individual differences. On the men’s side you also have guys who seem designed for monogamous mating and would not dream of having sex with a woman other than his regular partner. On the women’s side you have women who are really into short-term mating.

Women clearly have short-term mating strategies and they also have these individual differences. It’s important to recognize both: the general sex differences and the within-sex individual differences.

By Tracy Clark-Flory

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