Sex is All in The Brain

In politically correct circles, to assert that men and women are different borders on boorishness. If uttered by a man, such claims are evidence of naivety or a desire to shock, while from a woman they are close to a betrayal.

For the past twenty years, feminists have conspired with well-meaning male liberals to assert that all gender differences are the result of early conditioning. They have found it hard, admittedly, to explain why men are on average taller than women, since even the most intensive conditioning appears unable to add a cubit to our stature, but in terms of intellectual ability the assumption is that boys and girls begin with the same empty screen, on to which their parents and society at large project very different expectations.

Hampstead parents, many of whom actually believed this, have obediently declined to furnish their sons with guns, or their daughters with dolls. Blue and pink have been eschewed in favor of less obviously sexist colors. Around the growing boy the prison walls of the new man have begun to close almost from the moment of birth, while girls have felt failures if they want to become nurses rather than electricians.

Such is the frailty of fashion that this period of well-meaning behaviorism has actually coincided with growing evidence that men and women are very different indeed, and that these differences have little to do with their upbringing but lots to do with the chemical factors that distinguish them.

A growing body of scientific evidence now indicates that the brains of men and women are differently wired from very early in life as a result of sex hormones, and that this really explains the different abilities and skills of the two genders.

The recognition of this truth has come as a relief to many researchers who set out with other ideas. For example, Camilla Benbow of Iowa State University, who has demonstrated that high mathematical ability tends to be a male preserve, has said: “After 15 years of looking for an environmental explanation and getting zero results, I gave up”. She now accepts that these differences are biological in origin.

An excellent summary of the present state of knowledge is provided by Doreen Kimura, a professor of psychology at the University of Western Ontario, in the current issue of Scientific American. (A remarkable proportion of those working in the field of sexual differences are women, interestingly enough.) In Professor Kimura’s laboratory it has been shown that boys as young as three are better at target-directed motor skills in ordinary language, hitting or catching balls than girls of the same age. Nor is this a consequence of greater practice: boys simply appear better equipped by nature to become cricketers or baseball players.

By the same token, girls have greater verbal fluency, learn languages more easily, are better at remembering landmarks from a route and carry out some manual tasks more skillfully. While men will learn the route for a journey by rote “third left, second right, straight on at the roundabout” women will memorize it by landmarks, recalling that the right turn is close to Woolworths. The male approach makes men better at reading maps, according to Thomas Bever of the University of Rochester.

By running rats through mazes, Christina Williams of Barnard College has shown that these gender-related behaviors can be reversed. Newborn male rats deprived of the male sex hormone testosterone navigate like females, while masculinized females get around like males. The Darwinian explanation for this is that male mammals with several mates must navigate skillfully to find them all, a hypothesis given a useful head of steam by the finding that meadow voles, which are polygynous, show gender differences in navigation while the monogamous prairie vole does not.

Professor Kimura is in no doubt that the effects of early exposure to sex hormones are considerable, and lifelong. Girls with a genetic defect that exposes them to high levels of masculinizing hormones in the womb grow into women with spatial skills that are more typical of men.

Exactly how these differences arise is not yet clear, but the accumulating evidence is strong. The brains of girls and boys are made in a distinctive way that may determine how well they perform in certain specialized tasks.

This may mean that we may never see equal numbers of men and women in physics and engineering, or a woman chess master able to beat the best men. In other fields Professor Kimura suggests medicine, where perceptual skills are important women may in due course constitute a majority.

The fact that sex differences are real does not, of course, justify discrimination. In both sexes the range of ability is wide, with large areas of overlap; and most professions require a blend of skills which can be provided in more than one way. Nor do the inborn differences mean that environment is irrelevant.

But it is no longer good enough to pretend that there are no differences beyond those imposed by convention and social behavior, or that to look for such inborn differences is in some way an improper activity.

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