What Kinsey’s 75 Years of Sex Research Says About Us

Alfred Kinsey, the famed sexologist, founded the organization in 1947. He’d started studying human sexuality years earlier, when the university asked him to teach a course on marriage and family. To prepare, he looked for scientific research on human sexual behavior. Finding little, he conducted his own, and in the process changed the way we think about our sex lives.

Armed with a list of roughly 350 questions, Dr. Kinsey and other researchers criss-crossed the country interviewing thousands of Americans about their sex lives. This body of research formed the basis for two landmark books: “Sexual Behavior in the Human Male,” published in 1948, and “Sexual Behavior in the Human Female,” published five years later.

Kinsey-affiliated researchers—anthropologists, biologists, sociologists and psychologists—have since studied everything from reproduction and sexual health to homosexuality and gender development. Kinsey researchers were the first to conclude that sexual orientation is on a continuum and not an either/or. They held influential conferences on HIV and AIDS in the 1980s. More recently, they began a longitudinal study on the pandemic’s impact on our sexuality and intimate relationships.

“We are trying to take this experience that millions of people have every day and shed some light on the mystery of it,” says Justin Garcia, Kinsey’s executive director.

As the Kinsey Institute celebrates its 75th anniversary this week, I looked at a few of the top discoveries its researchers have made about our sex lives.

The Norm Isn’t Narrow

Dr. Kinsey’s work showed that people’s sex lives were a great deal more varied than previously thought. Prior to his research, married heterosexual sex about once a week in the missionary position was widely viewed as a normal, healthy sex life.

People also thought that sexual arousal is linear, that once something excites us, we keep going. And if that doesn’t happen, something’s wrong with us—we have a dysfunction or just aren’t trying hard enough.

In the 1990s, Kinsey researchers learned that arousal is governed by two biological systems, not one. Our excitation system, or gas pedal, revs us up, and an inhibition system, or brake pedal, slows us down. These systems—which researchers refer to as the Dual Control Model of Sexual Response—each have their own triggers and work independently. Some things, like kissing, turn us on. Others might turn us off (think: the kids walking in).

“Basically, we’re always weighing ‘Yes sex!’ and ‘Oh, not right now!’” says Erick Janssen, a Kinsey senior research fellow and professor of human sexuality at the University of Leuven, in Belgium, who co-authored the original research.

The findings, and numerous related studies, show that what turns us on and off varies by individual, colored by our personality, physiology and history. And these might change over time, Dr. Janssen says. (To learn more about your sexual gas and brake pedals, try Dr. Janssen’s questionnaire.)

Understanding this can help us in the bedroom and in our relationship. “If you start to identify your inhibitors and accelerators, this will help you cultivate the environment you need to be aroused and stay aroused,” Dr. Janssen says. “And it will also help you better understand your partner.”

Almost Everyone Fantasizes

At the time that Dr. Kinsey started his research, the prevailing view on sexual fantasies was Freudian: People who were happy didn’t have them.

Boy, was he wrong.

Since 2014, Justin Lehmiller, a social psychologist and research fellow at Kinsey, has been conducting one of the most comprehensive studies ever done on fantasies, which he defines as mental pictures you have while awake that arouse you. He’s found that 97% of respondents report having them.

People’s fantasies are remarkably similar around the world, Dr. Lehmiller says. There’s also a lot of overlap in what men and women fantasize about, with both saying that their fantasies include an emotional element.

People fantasized more during the pandemic, Dr. Lehmiller says, often not just for pleasure but to cope with stress, relax, distract themselves or feel less lonely. Many people also shared their fantasies with a partner. Those who did were more likely to report improvements in their sex life than those who didn’t.

“Fantasies are a healthy and adaptive part of human sexuality,” Dr. Lehmiller says. “And they can be a lifeline for a lot of people to tap into their deeper needs.”

The Journey Is the Destination

Kinsey researchers have conducted about 100 studies on orgasm. And they’ve shown that men don’t always have one during sex—contrary to what Dr. Kinsey himself assumed—and women do more than previously thought. It varies, especially as we age. And this is normal.

Connecting is the most significant aspect of our sexual experience, says Dr. Garcia, the executive director.

Other findings suggest pleasure for women has different triggers. “It’s all the accouterments that do the trick—the setting, the mood, kissing, petting, massaging,” Dr. Garcia says. And men and women both fake things, men typically because they’re embarrassed about losing arousal and women generally to please a partner.

And while climax is, of course, associated with satisfaction, studies show that there are many reasons why people have sex, Dr. Garcia says, from wanting to experience pleasure to wanting a partner to feel good. A consistently popular reason: “I wanted to express my love.”

“The beauty in our sexual lives is that they are a journey,” says Dr. Garcia. “And we should enjoy wandering that path and not be so focused on the end destination.”

Elizabeth Bernstein writes the “Bonds: On Relationships” column for The Wall Street Journal, which explores social psychology and the manifold aspects of human interactions. In her column, she focuses on how we can best relate—to others and to ourselves. Ms. Bernstein has been at the Journal for more than 20 years and has previously covered higher education, philanthropy, psychology and religion at the paper, all areas in which personal relationships loom large.