What We Know About Sex

USA WEEKEND Magazine and the world-famous Kinsey Institute team up for a special report to the nation. Topic: the most important things science has learned about sex. We've come a long way, baby.

A ubiquitous topic that no one likes to discuss. A highly private act that catches the public eye. Sublime. Dangerous. Compelling. Confusing. The most fundamental of human experiences, and the one responsible for the perpetuation our species. Sex.

In recent decades, America's sexual landscape has been rearranged by forces including new forms of contraception, skyrocketing divorce rates, a sea change in women's societal roles and an explosion of graphic media imagery. Even the idea of what constitutes sex -- think Bill Clinton and Monica Lewinsky -- has changed.

Today, USA WEEKEND Magazine teams up with the Kinsey Institute for Research in Sex, Gender and Reproduction to assess America's sexual health and understanding. The Indiana University-based research institute has created headlines for more than 50 years, ever since biologist Alfred Kinsey published "Sexual Behavior in the Human Male" and "Sexual Behavior in the Human Female" -- collectively known as the Kinsey reports. These landmark volumes shed the first scientific light on once-taboo topics, such as homosexuality, premarital sex and masturbation. The institute ( has continued to study human sexuality and has become the world's foremost repository of information about sex.

Sort through it all, says noted sex researcher and psychiatrist John Bancroft, M.D., director of the Kinsey Institute since 1995, and "the United States is in a mess, as far as sex is concerned." For instance, nearly half of all pregnancies are unintended, with 835,000 teenage pregnancies annually; they are said to cost the United States as much as $15 billion a year.

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Research into human sexuality could help improve these dismal numbers, as well as unravel significant medical and psychological mysteries, Bancroft says. Unfortunately, societal discomfort about sex marginalizes -- and sometimes condemns -- scientific sex research. As a result, he concedes, "It's difficult to think of any important aspect of the human condition about which we know less."

Nonetheless, sex researchers have made progress in psychological and physiological fields. Below is Bancroft's list of today's most important findings on sex.

Sexuality defines our lives. Sexuality is central to all of us -- even people who aren't sexually active. "It's absolutely fundamental to the organization of human society and has been from the earliest history," Bancroft says.

Studies show that sexuality plays a significant role in our self-esteem and emotional well-being. "For most people, what they think about themselves as a sexual person is a very important part of how they think about themselves as a human being," Bancroft explains. "The effect of having a good sexual relationship on one's well-being is very substantial." A 2000 Kinsey survey found that general physical and mental health were strongly correlated to sexual well-being and satisfaction. Poor health tended to increase sexual problems and decrease desire.

There's no "normal." Decades of scientific inquiry have made clear that sexuality exists on a continuum: No two people are exactly the same in their level of sexual interest, patterns of response or interests. And because of this variability, there really is no such thing as a "normal" frequency of sexual activity or a "normal" number of fantasies. "What is right for two people in a relationship is what works for them," Bancroft says.

Women and men have different needs. Kinsey was one of the first to question the assumption that female sexuality has the same basis as male sexuality; his findings showed that only a minority of women achieve orgasm through intercourse alone. Continued research has demonstrated the complexity of women's sexuality. A 2003 Kinsey study found that the quality of women's emotional interaction with their partner during sex proved more important than the physical aspects, such as orgasm, in determining sexual satisfaction.

Intimacy becomes more important with age. Although sexual interest and the ease of sexual response tend to decrease with age, the quality of the sexual relationship need not deteriorate. In an AARP survey of close to 1,400 adults over 45, two out of three of those with partners said they were extremely or somewhat satisfied with their sex lives. "Provided both partners can be open with each other, the importance of their sexual relationship may shift in emphasis from shared pleasure to shared intimacy," Bancroft says. Unfortunately, normal changes associated with aging -- especially men's inability to achieve consistent erections -- often are misinterpreted as a relationship failure.

Help has been found for male dysfunction. About 5% to 10% of men under 50 have erection problems due to a host of medical and psychological conditions, a number that increases sharply with age. Compared with some of the very unwieldy treatment methods that have evolved over the past 20 years, including penile implants and injections, the introduction of Viagra and drugs like it has been revolutionary. "Although it's not without side effects, it's available, it works for most people, and there wasn't anything like it there before," Bancroft says. Meanwhile, there's a push to find an equivalent drug for women, a search complicated by the fact that genital response is far less central to women's experience than erections are to men's. Low sexual interest is the most commonly reported sexual problem in women; researchers are trying to determine how often it is hormonally based.

Orientation isn't a choice. Research shows most people become aware of their sexual orientation around puberty and perhaps as early as age 10. Findings such as the discovery of the so-called gay gene have shown that genetics play a role in determining why a minority of people end up with a same-sex orientation, but Bancroft holds that genes are "just part of the picture. There are far more questions than answers."

Being ill -- and taking medicine -- can cause sexual problems. Many common medical conditions, such as depression and high blood pressure, can cause sexual problems. One of the downsides to modern medicine, however, is that the medications used to treat those conditions also can negatively impact sexual functioning. And although Bancroft says he was pushed aside when he tried to research this issue in the 1970s, it has been taken more seriously in the medical community recently.

The 2003 Kinsey study found that negative side effects on sex and mood were the most likely reason for women to discontinue oral contraceptives -- sexual impairment was cited by 86% of women who discontinued. "This is an important aspect of women's reproductive health that has not received the attention that it should from the medical profession and the pharmaceutical industry," Bancroft says.

The media create sexual expectations. The publication of Kinsey's work 50 years ago generated a crush of media coverage. "There was shock sometimes, and horror sometimes, and amazement at how much people were doing [sexually]," Bancroft says. "Now there seems to be a preoccupation with how little people are doing."

Indeed, recently headlines have screamed that Americans are sex-starved. But Bancroft isn't so sure there's any scientific substance behind the hype. "We haven't got any clear evidence that this is the case, but that doesn't seem to deter [the media]." The reality of our sex lives is probably far less dramatic than the media would have us believe.

Technology transforms sex lives. When photography became widely available at the end of the 19th century, it soon was put to use to provide erotic images. More recently, the Internet has been both a boon and a menace to healthy sexuality. Although it provides access to very personalized information and can serve as a means of support and connection for those whose sexuality makes them feel isolated, others are unable to resist the lure of interactive Internet pornography, a fact Bancroft deems "quite scary."

Because an extraordinary variety of sexual stimuli is accessible in relatively private settings, he maintains that Internet erotica is potentially far more dangerous than traditional print or video sources and can interfere with relationships and work performance while emptying bank accounts. The National Council on Sex Addiction and Compulsivity estimates that a staggering 2 million Americans are addicted to cybersex.

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4 ways to improve America's sexual health

John Bancroft, M.D., director of the Kinsey Institute, provides his prescription for a healthier society.

Eradicate the sexual double standard. "Until we have achieved a society in which sexual responsibility is equally shared by men and women, from early adolescence onward, we will continue to have major social as well as personal problems associated with sex."

Teach sexual responsibility to young people. "The expectation is that young people will spend their years of maximum sexual arousability in a society that bombards them constantly with sexual messages in a state of 'suspended sexuality.' It does not help to deny information to adolescents when they are experiencing sexual feelings. It is also not possible to teach our youth to behave in a responsible manner without being open and honest about sex."

Respect all varieties of sexual expression, as long as they are handled responsibly. Sexual responsibility, Bancroft says, means protecting against disease and unwanted pregnancy, avoiding causing physical or psychological harm to ourselves and our partners, participating only in truly consensual sex and avoiding sexual exploitation of those too young to make responsible decisions.

Encourage trust. Being sexual means letting go. Feeling safe to do so with a partner has a powerful bonding effect. Conversely, many sexual problems result from not feeling safe or from being hurt while vulnerable.

Kinsey, the movie

The historic, sometimes demonized work of Alfred Kinsey is coming to the big screen. "Kinsey", starring Liam Neeson, is expected in theaters next fall.

"He's a really fascinating, complicated guy," says writer-director Bill Condon, who wrote the screenplay for the Academy Award winner "Chicago", "but the thing that makes it compelling is that the questions he raised are still relevant."

The Kinsey Institute is not formally involved in the production but made materials --including personal scrapbooks and letters -- available to the filmmakers.

Condon is "bracing for controversy" surrounding the film, but don't expect anything too heavy: "It's about sex, so it can't help but be funny."

Sex by the numbers ...

We're monogamous in marriage

Women: more than 80%

Men: 65% to 85%

We think about sex ...

Every day:

Men, 54%;
, 19%

A few times a month/week:

Men, 43%;
Women, 67%

Less than once a month:

Men, 4%;
Women, 14%

Frequency of sex

Ages 18-29: Average 112 times a year

Ages 30-39: Average 86 times a year

Ages 40-49: Average 69 times a year


90% of sexually active women and their partners use contraception, although not always consistently or correctly. Sexually transmitted diseases 15 million new cases a year

Cover photograph by Simon Watson, Getty Images.

next: Guidelines for Diagnosis and Treatment of Sexual Dysfunction

APA Reference
Staff, H. (2005, November 1). What We Know About Sex, HealthyPlace. Retrieved on 2024, July 21 from

Last Updated: August 21, 2014

Medically reviewed by Harry Croft, MD

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