[Book Summary] Why Do Women Have Sex? — The Complex Inner World of the Human Animal Revealed by 237 Motivations

"Because I love him"—scientifically, this answer accounted for only 8%.
When you learn what lies in the remaining 92%, you will likely see the creature known as "human" in a slightly different light.

Key Points

Clinical psychologist Cindy Meston and evolutionary psychologist David Buss asked 1,006 women around the world, "Why do you have sex?" The answers they received numbered 237.

From simple motivations like "I was sexually attracted" or "I wanted to feel good," to "I wanted to cure a headache," "I wanted to get closer to God," "for revenge," "to punish myself," or "to get a job"—the range of motivations spans the entire spectrum of desire, strategy, fear, duty, and spirituality.

The long-held conventional wisdom that "men have sex for pleasure, women for love" is quietly dismantled in the face of this data. What defines female sexual behavior is neither love nor instinct, but a much more complex "web of reasons."

Recommended for

• Those who have felt that the premise "human sexual behavior can be explained by love or instinct" is somehow insufficient.

• Those who want to think about "why humans behave in such strange ways" from the intersection of psychology, evolutionary theory, and clinical research.

Book Information

Authors:Cindy M. Meston, David M. Buss
Translator:Kanako Takahashi
Publisher:Kodansha
Japanese Edition Published:June 13, 2012
Price:1,980 yen
Genre:Sexual Psychology, Evolutionary Psychology, Clinical Psychology, Science Non-fiction

About the Authors

Cindy M. Meston is a professor of clinical psychology at the University of Texas at Austin and a leading expert in the study of women's sexual psychophysiology. She has authored over 100 papers and books on female sexual response, and in 2003, she led the International Society for the Study of Women's Sexual Health, continuing to bridge the gap between pure academic research and clinical practice.

David M. Buss is also a professor of evolutionary psychology at the University of Texas and is known as "one of the most cited researchers among living psychologists." He has authored widely read books in Japanese such as "The Evolution of Desire" and "The Dangerous Passion: Why Jealousy Is as Necessary as Love and Sex," and has consistently discussed human mate selection, jealousy, and sexual competition within the framework of evolutionary theory.

The two first co-authored a paper titled "Why Humans Have Sex" in the academic journal *Archives of Sexual Behavior* in 2007, and following the shocking response to it, they wrote this book, narrowing the focus to women and delving deeper.By teaming up, the two with different specialties created a rare, dual-structured research book that dissects sexual behavior from both "biological impulses" and "psychological and contextual motivations."

I. The Half-Century That Didn't Ask "Why"

In 1948 and 1953, Alfred Kinsey surveyed the sexual behavior of over 8,000 Americans and presented it to the world as the "Kinsey Reports." It had a major impact on society at the time, but it was fundamentally a survey that asked "How."

For the next 50 years, sex scientists continued to refine the same questions—"how often," "with what kind of partner," and "what kind of acts."

But "Why" remained unasked. This was because everyone believed they "already knew" the answer.

"People have sex for pleasure, for love, and for reproduction"—this three-word answer went unquestioned for nearly a century.

Meston and Buss drove a wedge into this.

To prove that the "already known answer" was surprisingly poor, they asked 1,006 women directly: "Tell me every reason you have ever had sex."

II. The Meaning of the Number 237

When organized, the motivations returned amounted to 237 types.

Researchers broadly classified these into four categories: "physical motivations," "goal-attainment motivations," "emotional motivations," and "motivations based on insecurity/instability."

However, the specific content of individual motivations is far more eloquent than the classification itself. The most frequently cited motivations include "because I was sexually attracted to the person," "because I wanted to feel good," and "because I wanted to show affection." These appear to be "conventional" answers.

But the range of these 237 motivations extends much further.

• "Because I wanted to get rid of a headache" (medicinal motivation)

• "Because I wanted to get closer to God" (spiritual motivation)

• "To make a rival jealous" (status-competitive motivation)

• "To make them break up" (relationship-destructive motivation)

• "Because I wanted to punish myself" (self-harming motivation)

• "Because I can get money" (resource-acquisition motivation)

• "Because I wanted to give the partner an STD" (harmful motivation)

An action with such a wide-ranging "map of reasons" is extremely rare among human behaviors.

There are no such diverse motivations for eating or sleeping.

The number 237 indicates that sexual behavior is an act that takes on the entirety of human social and cognitive complexity, which cannot be explained by "instinct" and "pleasure" alone.

III. The Collapse of the Conventional Wisdom That "Women Do It for Love"

The conventional wisdom that this book most vividly dismantles is the schema that "women have sex for love."

In the survey, the percentage of women who cited "to express love" as a motivation for sexual behavior was only 8%.

On the other hand, 32% of men cited "love" as a motivation—in other words,the motivation of "sex for love" was actually higher among men.

This reversal holds more significance than a simple statistical surprise.

It suggests the possibility that the gender stereotype that "women are emotional and men are instinctual" was the exact opposite of reality.

The top three motivations for women were "attracted to the person," "physical pleasure," and "it feels good"—all of which placed the "body" before "love."

IV. Sex as a Strategy: Resources, Status, and Competition

One of the most stimulating chapters in this book is the analysis of the behavior of "using sex strategically."

The motivation of "sex to get what I want" is recorded in multiple forms.

Sex for promotion or employment (resource acquisition), sex to make a rival jealous (status acquisition), sex to keep a cheating partner (relationship maintenance), and sex to steal someone else's lover (competitive strategy)—these are all behaviors accompanied by a cool-headed sense of purpose, distinct from "pure desire" or "pure love."

From the perspective of evolutionary psychology, these are viewed as "adaptively calculated behavior"—that is, the interpretation is that they are not unethical deviations, but part of a repertoire of strategies formed by evolution.

V. Dark Reasons — The Existence of Coercion, Fear, and Obligation

What makes this book decisively different from other sexology books is that it honestly records "dark reasons."

Among the women who participated in the survey, many experiences of "unwanted sex" were reported—those due to verbal coercion, those involving alcohol or drugs, and those that were an extension of childhood abuse.

The authors did not exclude these as "exceptional cases" but included them as part of the overall motivation map. This is because if the question "Why do women have sex?" is to be truly sincere, it must visualize not only voluntary desire but also coercion, fear, and obligation.

This choice elevates this book from a mere "interesting statistics book on sex" to...a "scientific book that looks squarely at the ethical complexity of human sexual behavior."

Summary

Interpretation 1 — The 237 motivations are an "inventory of self-deception"

If you re-read this book from a psychoanalytic perspective, many of the 237 motivations may be "post-hoc verbalizations of unconscious motives."

When humans tell a story after the fact about why they took a certain action, they tend to choose "socially acceptable motives" rather than the actual ones—this is called "rationalization."

If so, the question arises:how many "true motives" are there within the number 237?

Were the women who answered "because I was bored" really bored? Or perhaps they just couldn't verbalize the motive of "wanting to be needed by someone."

The data in this book is a catalog of "reasons for sex," and at the same time, it is a mirror that illuminates "how little humans know their own desires"—that is how it can barely be read.

Interpretation 2: "237" is a symptom inventory created by the pressures of civilization

If you ask animals other than humans "why do you mate?", the answer is one word—"instinct."

However, the reason human women's answers became 237 types is that only humans have a "cognitive system that gives meaning to sexual behavior."

Here is one wild interpretation: are many of the 237 motivations "the result of cognitive functions that originally developed for purposes other than sex hijacking sexual behavior?"

"Sex for status" is a hijacking of status desire, "sex for revenge" is a hijacking of aggressive impulse, "sex to get closer to God" is a hijacking of transcendental desire—even if civilization forbids "do not give meaning to sex," the brain tries to connect sexual behavior to every possible goal. The number 237 might be read as the "total number of symptoms" created by the collision between the suppression of civilization and human cognitive flexibility.

Interpretation 3 — The question "Why ask only women?" is itself part of the answer

The original title of this book is Why Women Have Sex—it is a survey book specialized for women.

The authors explain the reason as "women may have higher initiative in decision-making regarding sexual behavior in short-term sexual relationships."

But the question "Why ask only women?" contains a much deeper structure.

Isn't the asymmetry itself—where men's motives for sexual behavior are considered "self-evident" and only women's motives are studied as a "mystery"—a remnant of history where society treated men's desires as the norm and women's desires as a deviation?

In this interpretation, the list of 237 motivations is more than just "proof of the complexity of female sexual psychology"; it is also "proof of the simplicity of a society that did not ask about men's motives."

If the same survey were conducted on men, that would also be over 237—except that no one thought it was a "mystery."