Some women dodge sex by feigning a headache, while others seek out orgasms as a surefire migraine cure. Some women pursue one-night stands to ease their loneliness, while others find that such trysts only deepen their solitude.

Those are among the seeming contradictions Cindy Meston, PhD, has found in her studies of women and sex. In fact, you can’t generalize much when it comes to why women have sex or the consequences of those experiences, says Meston, who directs the Sexual Psychophysiology Laboratory at the University of Texas at Austin. Along with fellow Austin researcher David Buss, PhD, Meston asked 1,006 women — from 2006 to 2009 — to divulge and discuss their sexual motivations for the book “Why Women Have Sex” (Times Books, 2009). The reasons ranged from the adventurous to the vengeful, including wanting to “see God,” hoping to secure a job promotion, staving off boredom and preventing a mate’s infidelity.

Having studied women’s sexuality for 20 years, Meston decided to focus on the why of having sex and was surprised by the diversity of reasons.

The Monitor talked with Meston about women’s sexual motives, her other sex research and whether women get help on par with men for their sexual problems.

What surprised you most about why women say they have sex?

The range of reasons. Some women just want their partners to feel good about themselves. Some have very, very negative reasons, including revenge, “mate poaching” and even trying to give someone a sexually transmitted disease. That was a pretty low-frequency response, but if you have one in 1,000 women doing that everywhere, which is close to what we found, it can have deleterious consequences.

The fact that so many women were defying gender stereotypes was also interesting. We found that often women are the initiators, really want it for the pure pleasure of it or want to have sex simply to get rid of their virginity. The younger women in our study were embarrassed by their virginity and wanted to be sexually experienced. They also wanted to see what sex was like with men of different ethnicities and ages, men with different jobs and penis sizes.

What were the top motivators for sex?

Not surprisingly, the main reason was “sexual attraction.” “Pure physical gratification” was the next big category, which included items such as because it was “fun,” it was “exciting.” They wanted pure gratification without commitment. The next big category pertained to love and commitment. They wanted to show their partners they were in love, wanted to strengthen the bond and feel emotionally connected to the person.

This book follows your 2007 “Why Humans Have Sex” study with Buss. Why did you focus on women this time?

I thought people would be more interested in reading about women because they are much more complex sexually. The whole physiology is different in women. There are three FDA-approved drugs to enhance sex for men, but none for women. These drugs increase blood flow to the genitals, they give a man an erection, and he notices it and interprets it as sexual arousal. Whereas a woman — and we did some of the original studies of Viagra-like drugs in my lab — can have the same engorgement in the genitals and not notice it. If they do notice it, it doesn’t necessarily make them feel aroused. It’s easier to arouse a man. It’s easier for him to want to have sex because he’s aroused. But in women there are so many other things going on both internally, like body image, and contextually, from how their partners treated them that day to what their children are doing. All these things impact their psychological experience of arousal. It’s harder for women to tune these things out and just focus on the physiological genital sensations.

You and Buss conducted the study via the Internet. What were the pros and cons to e-surveying?

Internet survey is a way to get a better representation because you aren’t just getting people within your area of the country. But you are appealing to people who are on the computer a lot. That’s a younger, higher-socioeconomic-status demographic, which is why we also advertised in newspapers and, if people preferred to do the survey by mail, we would mail it out to them to send back in. Face-to-face surveying is hugely admirable, but very time-consuming and terribly expensive. People could lie or make up stories just as easily as on a questionnaire. I think it’s easier to guarantee confidentiality and anonymity through an Internet survey.

Most of your book’s examples are from heterosexual women. Will your findings speak to lesbians?

There aren’t huge differences in most aspects of sexuality — orgasm, arousal and drive are the same physiologically regardless of orientation. We included several stories from bisexual and homosexual women, but the base rates are much lower; 94 percent of women are heterosexual, so there weren’t as many quotes from nonheterosexual women to choose from. About 7 percent of our respondents noted they were gay or bisexual. We also had a variety of write-in categories, which included bi-curious, polyamorous, still questioning, straight-plus, fluid and “mostly heterosexual, plus a touch of gay.”

You’re doing some work on sex and SSRIs. What effect are they having on women’s sexuality?

A huge effect. A very large proportion of women on SSRIs report sexual concerns. Now, it’s a little hard to tease apart, because if the woman was depressed and went on antidepressants, then likely the depression decreased her sex drive. So, did the medication decrease it further? Sometimes it’s hard to compare to pre-depression levels. The good news is the newer generation of antidepressants, such as Wellbutrin, Celexa, Remeron and Serzone, have fewer sexual side effects.

Do medical professionals tend to talk much with women about sexual problems or sex drive?

Absolutely not. It’s a huge problem, and it’s a topic that comes up again and again at professional meetings. When women have sexual problems, questions or concerns, physicians for the most part don’t want to hear it, partly because there is very little, if any, sexuality training for interns. Even most ob-gyns have only about a half-day of training on conducting sexuality interviews. So they don’t know much about it, they don’t want to talk about it, they don’t know what to do with the answers, they don’t know who to refer to, and they don’t know how to treat it, partly because there aren’t good treatments for women’s sexual dysfunction. And so a lot of them say “Try testosterone,” which hasn’t been approved by the FDA, but clinicians are prescribing it like crazy because it’s all they have in their tool bag. And it has some negative consequences, such as mood changes and unwanted facial hair.

What do you want to know more about in terms of women’s sexuality?

Sexual arousal is one area. Arousal can be physiological or psychological. Psychological arousal and desire are hard to tease apart in women. It’s so embedded in relationship issues, in culture and ethnicity, religion, body image, education, sexual education, self-confidence, and many other things. Meanwhile, lack of desire is what most women are complaining about, and we don’t have any empirically validated psychological treatments or drug treatments to address desire.

What else are you working on?

We have 23 studies currently ongoing in my lab. One of my graduate students is looking at the effects of nicotine and smoking on sexuality. Nicotine is known to be a real killer of the erectile response. He is doing an amazingly difficult longitudinal study of men who are long-term smokers with erection problems. He is measuring their erectile response before and after a smoking cessation treatment to see if there’s recovery and how long it takes.

Another big project is my five-year NIH study, which is a treatment outcome study for women with severe histories of child sexual abuse who have sexual problems. We know that a large proportion of abused women have sexual problems in adulthood. Some tend to engage in a lot of high risk, indiscriminant sex and others have no sexual desire. But we don’t know what the mechanisms are that cause that. In addition to conducting a lot of psychological assessments, we are measuring their hormones and their sympathetic nervous system activation to find out. We know that a certain amount of nervous system arousal is beneficial for sexual arousal in women, but too much can impair arousal. It’s possible that these women have such a high baseline level of nervous system arousal due to their trauma that their sexual arousal response is negatively affected.

Are there still taboos about doing sex research?

Sadly, there still is this stereotype that because you’re a sex researcher, you are oversexed or obsessed with it. Or you have some deep, dark perversion you are trying to resolve. Only a couple of weeks ago, I was talking to a well-educated woman I know. She’d read my book and said, “So, you must have been really promiscuous as a teenager.” I was just absolutely stunned out of my mind.

I chose this field because I worked in a lab with a researcher who was studying rat sexual behavior. I discovered that very little research had been done since Masters and Johnson, and it seemed like an important and interesting area to go into.