“If a society puts half its children into short skirts and warns them not to move in ways that reveal their panties, while putting the other half into jeans and overalls and encouraging them to climb trees, play ball, and participate in other vigorous outdoor games; if later, during adolescence, the children who have been wearing trousers are urged to “eat like growing boys,” while the children in skirts are warned to watch their weight and not get fat; if the half in jeans runs around in sneakers or boots, while the half in skirts totters about on spike heels, then these two groups of people will be biologically as well as socially different. Their muscles will be different, as will their reflexes, posture, arms, legs and feet, hand-eye coordination, and so on. Similarly, people who spend eight hours a day in an office working at a typewriter or a visual display terminal will be biologically different from those who work on construction jobs. There is no way to sort the biological and social components that produce these differences. We cannot sort nature from nurture when we confront group differences in societies in which people from different races, classes, and sexes do not have equal access to resources and power, and therefore live in different environments. Sex-typed generalizations, such as that men are heavier, taller, or stronger than women, obscure the diversity among women and among men and the extensive overlaps between them… Most women and men fall within the same range of heights, weights, and strengths, three variables that depend a great deal on how we have grown up and live. We all know that first-generation Americans, on average, are taller than their immigrant parents and that men who do physical labor, on average, are stronger than male college professors. But we forget to look for the obvious reasons for differences when confronted with assertions like ‘Men are stronger than women.’ We should be asking: ‘Which men?’ and ‘What do they do?’ There may be biologically based average differences between women and men, but these are interwoven with a host of social differences from which we cannot disentangle them.”