In 1997, a study claiming to explain why boys will be boys and girls will be girls sparked a revealing outcry. British scientists had been studying girls with Turner's Syndrome; these girls have one X chromosome instead of two, and they tend to be insensitive and socially inept. As Time put it, "They act, in other words, a lot like boys."

Most daughters inherit an X chromosome from each parent. The study found that the Turner's Syndrome girls who got their single X from their mothers--as all boys do--were far more anti-social than girls with a paternal X. The researchers speculated that a social adjustment gene linked to the X chromosome is activated only if the X comes from Dad and thus is active only in girls.

"Experts Say Men Are Programmed to Behave Badly; 'Social Gene' Makes Lasses Nicer Than Lads," cried the headline in a London tabloid. "Preposterous," scoffed feminist writer Susie Orbach in the more highbrow, left-leaning British daily The Guardian. "Gender roles are culturally prescribed--they've nothing to do with genetics."

But were either of these sweeping statements grounded in reality? On a standardized index of anti-social behavior reported by parents, the average score for Turner's girls with a maternal X was nine out of 24. But if the "social gene" theory is right, Turner's girls who get their single X from their fathers should have been as socially skilled as normal girls. Yet boys and Turner's girls with a paternal X both averaged about 4 on the anti-social index. Normal girls had an average score of 2. There was also a good deal of overlap among the scores of normal children: Three out of 10 boys were as nice as five out of 10 girls. That's a difference, to be sure, and quite possibly a genetic one--but hardly one that indicates men are from Mars and women from Venus.

The Two Poles of Sex

The "social gene" brouhaha is all too typical of how we now talk about sex differences: Biology is either everything or nothing; men and women are identical or polar opposites. Many feminists absolutely refuse to allow that some of the gender-based inequalities they deplore may be due in part to innate differences. Many conservatives just as dogmatically invoke sex differences, often distorted or magnified beyond recognition, to condemn any departures from traditional roles. Neither side has much patience for the complexities of real life or for the variety of real people.

For example, in an August 1995 New York Times op-ed piece, conservative writer Danielle Crittenden argued that men's "genetic wiring" makes them immune to "the mental strain of walking out the door" that working mothers suffer. Irate readers dismissed this as absurd and asserted that any such feelings arise from "cultural conditioning."

It is hardly absurd to think that the parent who gives birth may have a biological predisposition to be more attached to the baby. On the other hand, a biological predisposition is not a universal imperative. Men thrust into a "Mr. Mom" role because they are out of work when the baby arrives often feel heartbroken when they have to walk out the door.

These extremes--polarity vs. sameness--are entrenched in mainstream culture. The notion that without sexist discrimination, half of all chief executive officers, engineers, and firefighters would be female is, paradoxically, matched by the equally pervasive notion that women and men are worlds apart. A May 1994 Newsweek story on gender in cyberspace says that women want computers to "meet people's needs," while men want to explore and conquer. In April 1998, The New Yorker ran two articles about how women will remake government and business in a collaborative, nurturing, consensus-oriented mold. A U.S. News & World Report story on women architects in October 1996 states that, unlike men, they place human needs above the ego and "collaboration" above "individual brilliance."

The evidence for such claims is usually underwhelming. If 58 percent of women and 46 percent of men tend to favor an activist government, that mutates in the minds of analysts into "fundamental differences" on issues and values--even if, in the same poll, 44 percent of men and 49 percent of women agree that "government should do more to help needy Americans even if it means going deeper into debt."

It is sometimes suggested that to deny differences between the sexes is a willful blindness to reality. But all those grandiose pronouncements about men and women often seem no less at odds with how actual human beings behave.

When the women-only sailing crew of America3 raced for the 1995 America's Cup, the media readily picked up team sponsor Bill Koch's favorite theme: Women (unlike men) don't have a problem subordinating their egos to the team. Yet an earlier all-female team, the U.S. Women's Challenge in the 1993 Whitbread race, was plagued by rivalries that prompted ousted skipper Nance Frank to lament, "Basically, there's no difference between men and women."

When John Gray, author of Men Are From Mars, Women Are From Venus, took his act to Broadway, a celebrity member of his on-stage panel, the supermodel Frédérique, wouldn't play along, declaring, "I relate a lot more to the Martian side." Gray scrambled for a face-saving answer that stood his basic conceit on its head, saying that women are "both Martian and Venusian." Yes, and so are men.

What's the Difference?

In recent years, even feminism has embraced gender differences and "female values" such as cooperation, nurturance, and pacifism. Although antipathy to "male" individualism and competition was part of the women's movement in the 1970s, "difference feminism" became ascendant after the publication of the 1982 book, In a Different Voice, by Harvard psychologist Carol Gilligan. Gilligan contrasted women's "ethic of care," based on human needs and relationships, with "male" moral reasoning based on rights, justice, and abstract principles.

"Difference feminists" usually skirt the question of where the difference originates, though Gilligan dances on the edge of arguing that childbearing gives women "easier access...to the fact of human connection." This evasiveness has earned them some ridicule: Journalist Robert Wright pokes fun at Deborah Tannen, author of the 1990 best-seller You Just Don't Understand: Men and Women in Conversation, for arguing that boys "learn" to jockey for status in their more hierarchical networks, without explaining "why the boys' groups are always more hierarchical in the first place." (That always, as we shall see, is quite an overstatement.)

Wright belongs to a school of thought known as evolutionary psychology (represented by his 1994 book The Moral Animal and by such recent works as Matt Ridley's The Red Queen and Steven Pinker's How the Mind Works). This school holds that la différence is a product of reproductive strategies that evolved to ensure genetic survival. The male, who can increase his progeny by having many mates, is "programmed" to wander and to seek dominance. The female, for whom parenthood is time-consuming, saves her favors for males who have good genes or who are willing and able to "invest" in her and her young. He looks for youth and attractiveness in a mate (signs of fertility); she looks for status and resources. Even if these patterns aren't relevant in an industrial society, they are "hard-wired" into our brains by millennia of evolution.

The political implications of this theory can cut both ways. Wright and Ridley invoke it to support affirmative action: Since men's advancement is propelled by their greater lust for power, often unrelated to merit, women must be favored "not to redress prejudice but to redress human nature." Others, such as Wayne State University law professor Kingsley Browne, argue that in the light of the new Darwinian science, male dominance in the public sphere is natural. And some evolutionary psychologists take issue with the view of women as less power-hungry. Primatologist Sarah Blaffer Hrdy points out that female apes compete for status quite aggressively, if less flamboyantly than males.

Our genetic heritage may shed light on many things about men and women. But we should heed philosopher Thomas Nagel's warning against "the ludicrous overuse of evolutionary biology to explain everything about life, including everything about the human mind," particularly since scientific knowledge of how evolution shapes the human mind is not just incomplete but highly speculative.

There is also much that science has yet to learn about hormones and brain organization, two other hot areas of research on sex differences. For instance, findings of "masculinized" behavior such as increased play with "boyish" toys in girls exposed to high prenatal levels of male hormones (androgens) are ambiguous: Androgenized girls don't show elevated levels of physical aggression or rough-and-tumble play. In one study, contrary to the researchers' expectations, girls with twin brothers, who have some exposure to androgens in the womb, exhibited no unusually tomboyish behavior, while girls with an older brother did.

Nor does magnetic-imagery brain research lend itself to simple conclusions. In a much-publicized Yale study in which men and women used different parts of the brain when picking rhyming word pairs, more than 40 percent of the women--eight out of 19--thought like a man, so to speak, but no men showed a female pattern. Could this mean that women are less rigidly sex-typed? Maybe. But while another brain scan study from the University of Pennsylvania found some differences in brain metabolism, a third of the males and only four of the 26 females had "cross-sex" brain patterns.

Unisex feminism certainly has its inanities and its zealotry, aptly dubbed "biodenial" by Daphne Patai and Noretta Koertge in their 1994 book Professing Feminism. Feminist biologist Anne Fausto-Sterling argues that the very idea of two sexes is a cultural construct, since babies with genital or chromosomal abnormalities are neither male nor female. Some scientists report pressure to stop or bowdlerize sex difference research. In John Stossel's 1995 ABC special, Boys and Girls Are Different, Bella Abzug and Gloria Steinem dismissed such research as "poppycock" and "anti-American crazy thinking."

Yet the fascination with la différence can make truth a casualty too. Take an oft-cited study in which 1-year-olds were separated from their mothers by a barrier. The results were summed up by Stossel as, "Most boys try to knock the barrier down; most girls just stand there and cry for help"--a depressing image of feminine passivity.

Yet Stossel also acknowledged that when his crew tried to tape such an experiment they saw only the exceptions--boys crying, girls struggling to get out. In the original 1969 study, the girls cried almost twice as long as the boys, and boys were more likely to wander to the ends of the barrier (where it was latched). That was taken to mean that they were trying to solve their predicament. But in a more detailed analysis of these data published 10 years later, it turned out that the girls pushed at the barrier as much as the boys did and tried to open the latches more often; the boys who moved to the end of the barrier mostly just stood there. In a follow-up study of the children at 2, girls were no weepier than boys and were far more active problem solvers: More than 20 percent of them got out, compared with 7 percent of the boys.

One would have to be very unobservant or very stubborn to deny that some traits are more common in one sex than the other. But, as Stossel noted, "individual differences are often much greater than the differences between the sexes." Still his own comments about how we are "biologically hard-wired to be different" seemed to leave little room for individual variety, as did all his footage of girls with tea sets and boys with swords. We shouldn't forget all the girls we now see playing basketball or soccer, and even taking part in soapbox derby races where they now make up a third of the contestants; or the boys who care tenderly for a puppy or kitten.

The Evidence of Gender

Much as they diverge ideologically, difference feminists and biological determinists share a propensity for sweeping statements based on modest evidence.

In You Just Don't Understand, Deborah Tannen cites a finding by psychologist Campbell Leaper that 5-year-old girls interact in a "mutually positive" manner, while boys exhibit "negative reciprocity" by which one boy tries to control and the other withdraws. In fact, Leaper found virtually no sex differences among children 4 to 6. Between 6 and 9, the boys were a bit less cooperative and the girls noticeably more so: 42 percent of their exchanges were "mutually positive" compared with 21 percent of the boys' exchanges. But even older boys collaborated much more than they sought to dominate, and they exhibited very little "negative reciprocity."

On the traditionalist side of the political spectrum, law professor Kingsley Browne speaks of "substantial evidence for sex difference in the spontaneous emergence of leaders." His source is a review of studies showing that overall, in small groups working on a task, men emerged as leaders 58 percent of the time. The difference was largest in laboratory studies and barely present in natural settings (mostly college students working on class projects). Male leadership was also most likely in groups that met once for fewer than 20 minutes; the division was close to 50-50 if there was more than one meeting. In other words, the more the conditions of the study resembled the real world, the smaller the difference.

When within-sex variation is taken into account, most psychological sex differences are in the small-to-moderate range, meaning that the distribution of a trait or behavior between the sexes is somewhere between 52-48 and 66-34. Sometimes, the research at least partly corroborates the stereotypes; often, many pieces of the puzzle don't fit. Consider Tannen's basic claim: The social world of boys is hierarchical and concerned with power, while that of girls is egalitarian and concerned with intimacy.

One observation of same-sex pairs of preschoolers in the playground seems at first to back Tannen: Boys used "heavy-handed persuasion"--physical force or threats-in 22 percent of their conflicts, compared with 9 percent for girls; the percentages were reversed for "conflict mitigation." Yet both sexes settled about two-thirds of their conflicts by "moderate persuasion" (which included giving orders). And "conflict mitigation" did not always denote concern with relationships: It included indirect displays of anger, such as staging a fight between disputed dolls, and walking out of a conflict situation.

There is evidence that in dealing with conflict girls are somewhat more concerned with maintaining relationships and boys with asserting control. Yet plenty of research casts doubt on beatific visions of the warm, egalitarian girl "communities"--as does, of course, the personal experience of anyone who has been a girl. Boys' power contests are more often expressed in physical aggression. But according to behavioral scientist Diane Jones, "competition and asymmetric relationships are as much a part of female groups as male ones."

In an especially intriguing experiment, preschoolers in single-sex groups of four were given a film viewer designed so that a child could watch a cartoon through an eyepiece only if two others cooperated by turning a crank and pressing a switch. There was much more playful pushing and hitting among boys. But the girls weren't shy about giving orders, using putdowns, or even blocking the viewer so that another child couldn't watch. Moreover, girl groups tended to have "a single dominant individual," while boys showed "more equal participation" in viewing. Nor did the alpha females get to the top by being nurturing: They gave commands, hit, and disrupted others' viewing much more often than other girls.

The picture is equally complex when it comes to other truisms:

Men are competitive, women cooperative. In a survey in Minnesota schools in the early 1980s, 45 percent of students who scored above average on competitiveness were female. Kingsley Browne cites this study as proof that "competition...is a more unalloyed positive experience for boys." But being highly competitive had drawbacks--such as feeling too pressured--for young children of both sexes. By high school, this pattern disappeared for boys and almost disappeared for girls, and more competitive girls had a stronger sense of self-worth.

A few years later, another study found that when high school athletes rated the relative importance of various goals in sports, girls emphasized teamwork somewhat more than boys did, while the reverse was true for winning and learning to be tough. Yet the similarities were far greater: Both sexes ranked cooperation first, followed by fitness, self-esteem, character building, and finally competition.

Men are autonomous, women "relational." A 1971 study did find a dramatic gap: 80 percent of the women, but only half of the men, defined their identity in terms of interpersonal connections. By the 1980s, this difference had all but vanished. When San Francisco State University English professor Jo Keroes analyzed student essays on personal dilemmas they had faced, she expected men to focus on self-determination and women on relationships. To her surprise, "autonomous" themes prevailed for both sexes. Another study was construed by its authors as supporting Gilligan's thesis since college women scored higher on "intimacy" than on "autonomy"--but so did the men.

Men don't share their feelings (especially not with other men). When scholars Kathryn Dindia and Mike Allen analyzed more than 200 studies on self-disclosure, they found surprisingly minor differences: "If approximately 45 percent of men would disclose a particular item, approximately 55 percent of women would disclose the same information." Subsequent research supports this conclusion. Researchers Steven Duck and Paul Wright even question the cliché that women have intimate friendships while male buddies just do things together: Both, they say, "are attuned to caring, supportiveness," and other emotional aspects of friendship. Ironically, Duck and Wright admit to helping perpetuate "the fashionable dichotomy" in their earlier work: for instance, reading much into the finding that women's meetings with friends were usually spontaneous and men's were more often planned--on the basis of a 10-percentage-point gap.

Men deal with stress by trying to solve the problem, women by brooding or seeking emotional support. Actually, both women and men take the problem-solving approach most often, followed by support seeking and then by emotional responses such as self-blame and distraction. Are there differences? Some. In one study, men reported using problem solving as the coping technique of first resort 56 percent of the time in recent stressful situations, compared with 44 percent for women. But other methods lagged far behind for both women and men.

And what about Tannen's classic you-just-don't-understand scenario, where the woman complains about a problem to get sympathy, the man offers a solution, and she gets upset? Her evidence for this archetypal misunderstanding consists of anecdotes, obviously meant to illuminate us with a flash of recognition. But while it did just that for one of my male friends, another recalled Tannen vignettes in reverse when he sought sympathy from women who "snapped into an I-have-to-give-advice-right-now mode." And for one woman, the recognition involved herself in the "male" role of would-be problem fixer when talking to her mother.

Had Tannen wanted to cite research, it might have been difficult: Several studies that look at "nurturant" and "problem-solving" responses to another's distress have found slight differences--but no evidence of a gender gap that requires self-help books to bridge.

Women want love, men want sex. Gender differences in sexual attitudes and behavior are much more dramatic than in virtually any other area. It is surely overconfident to discount biology, as do the authors of the 1994 report Sex in America: A Definitive Survey, who flatly state that there is "no reason to believe these differences...reflect some sort of genetic imperative." Indeed, it would be strange if reproductive roles had no effect on men's and women's attitudes toward sex. In this sphere of life, evolutionary logic makes the most sense.

But any theory which reduces human motivation to a mechanism that works independently of conscious intent can lose touch with reality. Robert Wright asserts that in casual sex, "the worst likely outcome for the man (in genetic terms) is that pregnancy would not ensue." Never mind that in real-life terms, the worst likely outcome is that it would. Several studies confirm that, as evolutionary theory would predict, men are more distressed by a woman's sexual infidelity (a threat to paternal certainty) and women by a man's emotional attachment to another woman (a threat to resources). But that doesn't explain why anywhere from a sizable minority to a slight majority of men find emotional infidelity more distressing--or why more women say that they would consider divorce if their spouse had a one-night stand with a stranger.

Other studies point both to undeniable gender gaps and to much common ground. In the National Health and Social Life Survey (on which Sex in America was based), one in four women under 25, one in five women in their 30s, and about one in three men held a "recreational" view of sex. The most common outlook for both sexes was "relational," linking sex to emotional intimacy but not necessarily marriage. When respondents in another survey were asked to pick 10 out of 48 wishes that they would most want fulfilled, sex "with anyone I choose" was selected by one in 17 women and one in four men. Yet the wish that got the most votes from both sexes, 73 percent of the women and 58 percent of the men, was "to deeply love a person who deeply loves me."

Equity vs. Equality

Clearly, the way we think about differences and similarities between the sexes has major consequences. If there is no innate sex difference in ability or inclination to be a physicist or engineer, women's underrepresentation proves that they are held back by discrimination or social pressure. If there is a difference, one could still call for special programs for girls, perhaps at the cost of steering some away from fields that suit them better. Or one could just focus on equal opportunity--even if, when the dust settles, women would make up 30 percent of engineers (as psychologist Janet Hyde estimates from spatial ability tests) or fewer.

But that wouldn't do for the equality-über-alles school. When, on his Boys and Girls special, John Stossel asked Bella Abzug if equality meant equal numbers in every field, she fired back, "Fifty-fifty-absolutely." If this notion of equality is misguided, clinging to it can lead us to see sexism where there is none and pursue coercive social engineering--or even imperil lives, as when fire departments' fitness standards are weakened to accommodate women.

Yet assumptions based on seemingly solid data about sex differences can miss the mark. In her 1973 anti-feminist polemic, The Female Woman, Arianna Stassinopoulos (now Huffington) predicted that equal opportunity without artificial parity would lead to "a small rise in the numbers of women accountants, engineers or geologists but a big rise in the numbers of female physicians, psychiatrists, lawyers, clergymen." So far, she has been correct about engineers and geologists. But in 1993, about half of accountants in the United States were female.

The history of Title IX of the 1972 Education Amendments, which bans sex discrimination in school athletics, illustrates the difference between equity and numerical equality. The law is almost universally applauded for opening up unprecedented opportunities for girls and young women to compete in sports. But recently, Title IX has also been interpreted as requiring that similar proportions of male and female college students be involved in sports--even if fewer women are interested. To comply, excellent men's sports programs are being killed, so that a male student who wants to participate in sports has less opportunity to do so than his female counterpart.

But conservatives who criticize this trend sometimes seem to assume a static gender gap in levels of interest in athletics. Actually, girls' enthusiasm for sports has skyrocketed. So say not just statistics (girls now make up about 40 percent of high school athletes, up from 5 percent in 1971) but middle-aged men who coach children's teams.

Today, we are learning more about the biological roots of sexual identity. Yet at the same time, we are seeing fewer sexual divisions. In England, psychological tests show that sex differences found among older people on such items as "I often try to get my own way regardless of others" do not hold for those under 30--perhaps due less to changes in personality than to younger women's greater candor about such traits. American women have become less risk-averse players in financial markets; on the darker side of risk taking, they are catching up with men in problem gambling and in drug and alcohol abuse.

Indeed, most scientists who study the biology of sex differences agree that nature and nurture interact in complex ways: Our activities and environment can alter brain organization and hormonal makeup. If, as Kingsley Browne suggests, it's "adaptive" for a child to imitate same-sex models, girls surrounded by images of strong women, from athletes and political leaders to television and film characters, will probably grow up different from earlier generations.

Pink, Blue, or Khaki?

One way to inject common sense into this debate is to shift the focus from groups to individuals. Otherwise, "difference talk" has its dangers. A boy will do better on a math test than a girl 63 percent of the time--whatever the reason. But if you automatically assume that a male is better at math than a female, whether in hiring someone or in helping a student make a career decision, you'll be wrong nearly four out of 10 times.

Browne wonders why "a tendency for men to exhibit male traits and for women to exhibit female traits is inferior to a situation in which the traits are distributed at random." In a sense, he is right: If women make up 63 percent of people with one trait and 33 percent of those with another, that shouldn't be a problem. But if these unevenly distributed qualities are designated as male and female with no quotation marks, people may be hindered from developing or acting on "cross-sex" traits.

Such assumptions may also cause people to be judged, perhaps unconsciously, by sex-based generalizations. Men get 40 percent more speeding tickets when speed is measured by radar but 250 percent more when the judgment is made by an officer's naked eye--partly, perhaps, because of chivalry, but also because the real gender gap in speeding is reinforced by stereotypical expectations.

That men are more likely to think and act in some ways and women in others, and that every man or woman should be treated as an individual, are two ideas we ought to be able to hold at the same time. This means avoiding comments like, "Each sex seems to have a different definition of what constitutes success in life" (as Browne writes, quoting from a 1968 monograph by psychologists Joseph E. Garai and Amram Scheinfeld). Sexes don't have definitions of success; people do. But it also means accepting that in a nonsexist society, most corporate executives may be men and most "primary caregiver" parents may be women.

Such an approach also negates arguments for including women in various fields on the basis of their special strengths, given how unpredictably these strengths are distributed. Robert Wright suggests that affirmative action should be based on the premise that women are less prone "to sacrifice the organization's welfare to personal advancement," and hence good for business. But the world is full of women looking out for No. 1, and they would be far quicker than their meeker sisters to reap the benefits of quotas. Women managers, some studies show, may not even be more sympathetic toward employees' family problems.

Just as specious is the notion that women as women have something unique to contribute to human understanding. A woman who criticizes individualism, competition, or the elevation of reason over feeling will be in agreement with plenty of men, from Rousseau to Tolstoy to Marcuse. (Rachel Carson, sometimes cited as a female voice affirming an organic vision of the sanctity of life, drew her inspiration from Albert Schweitzer.) Given the range of "male" and even "white male" thought, it's unlikely than women can produce ideas entirely free of its influence; indeed, it would be ludicrous to try. Worse, "difference feminism" can become a new straitjacket for women: Gilligan and the authors of the 1986 women's studies bible, Women's Ways of Knowing, disparage women who see "male" individualism or rationality as liberating.

The trickiest part, perhaps, is applying an appreciation of sex difference and individual difference to personal life. If one in three young men and one in five young women think sex just for fun is great, that's enough of a gap for many girls who want romance to run into boys who want a romp--one reason generalizations strike a chord. But life confounds all dogmas, whether of sameness or of difference, so that men who value marriage and relational sex--and women who don't--are not uncommon.

Indeed, a 1983 critique of the sexual revolution by writer and psychotherapist Peter Marin argued that liberation had turned into disillusionment for many women and men alike, except that "men are less articulate, feel less justified than women in their public complaints." Likewise, the male-fear-of-commitment cliché may have been an excuse for many women to avoid confronting their commitment anxiety. So concluded two people who helped propagate the cliché--Steven Carter and Julia Sokol, authors of the 1984 best-seller Men Who Can't Love, whose 1993 follow-up was titled He's Scared, She's Scared.

One could point to the popularity of You Just Don't Understand or Men Are From Mars, Women Are From Venus as proof that relationship problems stem from living with a member of a different species whom we mistakenly treat as one of our own. But does it prove much beyond the fact that intimacy is messy and complicated? Don't mothers and daughters, fathers and sons, siblings, same-sex lovers feel at times that they must cross a labyrinth to reach one another? Mars-Venus advice promises a quick fix: You just pull out the blue file marked "men" or the pink one marked "women" instead of trying to deal with the other person's unique qualities, or with your own inadequacies.

In part, the fascination with difference is a justified response to the excesses of unisex feminism. Only in women's studies can a utopia where gender matters no more than eye color hold any appeal. Sexual differentiation in some sense is a profound human need. The idea of a child being raised as an "X," its sex known only to the parents--the premise of a story by Lois Gould published in an early issue of Ms. as a rousing statement of liberation--is likely to strike most people as deranged.

Some people, fed up with a feminist creed that simultaneously holds that women and men are the same and that women are innocents and men are beasts, welcome the message that we should accept our differences. But an armistice in the gender wars is unlikely to work if it focuses on acceptance of collective but not individual difference. A world divided into updated versions of pink and blue would be only marginally less progressive than a world of khaki uniforms.

Cathy Young (cathyyoung1@compuserve.com) is a REASON contributing editor. This article is adapted from her new book, Ceasefire: Why Women and Men Must Join Forces to Achieve True Equality, published by The Free Press.