Examining cognitive differences between the sexes can help us understand the sources of human abilities and limitations. We should not be deterred from that task by the fear that the findings will be misconstrued in harmful ways.

Forty-six years ago, in The Two Cultures, C. P. Snow famously warned of the dangers when communication breaks down between the sciences and the humanities. The reaction to remarks by Lawrence Summers, president of Harvard University, about the differences between men and women was yet another sign of a breakdown that takes Snow's worries to a new level: the wholesale denial that certain bodies of scientific knowledge exist.

Mr. Summers's comments, at a supposedly off-the-record gathering, were mild. He offered, as an interesting though unproved possibility, that innate sex differences might explain why so few women are on science and engineering faculties, and he told a story about how nature seemed to trump nurture in his own daughter.

To judge from the subsequent furor, one might conclude that Mr. Summers was advancing a radical idea backed only by personal anecdotes and a fringe of cranks. In truth, it is the other way around. If you were to query all the scholars who deal professionally with data about the cognitive repertoires of men and women, all but a fringe would accept that the sexes are different, and that genes are clearly implicated.

Innate Gender Differences

How our genetic makeup is implicated remains largely unknown, but our geneticists and neuroscientists are doing a great deal of work to unravel the story. When David C. Geary's landmark book Male, Female: The Evolution of Human Sex Differences was published in 1998, the bibliography of technical articles ran to fifty-two pages--and that was seven years ago. Hundreds if not thousands of articles have been published since.

This scholarship shows a notable imbalance, however: scholarship on the environmental sources of male-female differences tends to be stale (wade through a recent assessment of 172 studies of gender differences in parenting involving 28,000 children, and you will discover that two-thirds of the boys were discouraged from playing with dolls but were nurtured pretty much the same as girls in every other way); but scholarship about innate male-female differences has the vibrancy and excitement of an important new field gaining momentum. A recent notable example is The Essential Difference: The Truth about the Male and Female Brain, published in 2003 by Simon Baron-Cohen of Cambridge University, which presents a grand unified theory of male and female cognition that may well be a historic breakthrough.

"Exciting" is the right word for this work, not "threatening" or "scary." We may not know the answers yet, but we can be confident that they will be more interesting than, say, a discrete gene for science that clicks on for men differently than it does for women. Rather, it will be a story of the interaction of many male and female genetic differences and the way a person's environment affects those differences. Hardly any of the answers will lend themselves to simplistic verdicts of "males are better" or vice versa. For every time there is such a finding favoring males, there will be another favoring females.

Responding to Gender Research

Some people will find the results threatening--because some people find any group differences threatening--but such fears will be misplaced. We may find that innate differences give men, as a group, an edge over women, as a group, in producing, say, terrific mathematicians. But knowing that fact about the group difference will not change another fact: that some women are terrific mathematicians. The proportions of men and women mathematicians may never be equal, but who cares? What is important is that all women with the potential to become terrific mathematicians have full opportunity to do so.

Of course, new knowledge will not be without costs. Perhaps knowing that there is a group difference will discourage some women from even trying to become mathematicians or engineers or circus clowns. We--scientists, parents, educators, employers--must do everything we can to prevent such unwarranted reactions. And the best way to do that is to put the individual's abilities, not group membership, at the center of our attention.

Against the cost of the new knowledge is the far greater cost of obliviousness, which can lead us to pursue policies that try to make society conform to expectations that conflict with what human beings really are. In the study of gender, large and growing bodies of good science are helping us understand the sources of human abilities and limitations. It is time to accept their existence, their seriousness, and their legitimacy.

Charles Murray is the W. H. Brady Scholar in Culture and Freedom at AEI.