It is after all not the case that the role of women in science is the only example of a group that is significantly underrepresented in an important activity and whose underrepresentation contributes to a shortage of role models for others who are considering being in that group. To take a set of diverse examples, the data will, I am confident, reveal that Catholics are substantially underrepresented in investment banking, which is an enormously high-paying profession in our society; that white men are very substantially underrepresented in the National Basketball Association; and that Jews are very substantially underrepresented in farming and in agriculture.
And the relatively few women who are in the highest ranking places are disproportionately either unmarried or without children, with the emphasis differing depending on just who you talk to. And that is a reality that is present and that one has exactly the same conversation in almost any high-powered profession. What does one make of that? I think it is hard-and again, I am speaking completely descriptively and non-normatively-to say that there are many professions and many activities, and the most prestigious activities in our society expect of people who are going to rise to leadership positions in their forties near total commitments to their work. They expect a large number of hours in the office, they expect a flexibility of schedules to respond to contingency, they expect a continuity of effort through the life cycle, and they expect-and this is harder to measure-but they expect that the mind is always working on the problems that are in the job, even when the job is not taking place. And it is a fact about our society that that is a level of commitment that a much higher fraction of married men have been historically prepared to make than of married women.
It does appear that on many, many different human attributes-height, weight, propensity for criminality, overall IQ, mathematical ability, scientific ability [emphasis mine] -there is relatively clear evidence that whatever the difference in means-which can be debated-there is a difference in the standard deviation, and variability of a male and a female population.
And there are certainly examples of institutions that have focused on increasing their diversity to their substantial benefit, but if there was really a pervasive pattern of discrimination that was leaving an extraordinary number of high-quality potential candidates behind, one suspects that in the highly competitive academic marketplace, there would be more examples of institutions that succeeded substantially by working to fill the gap. And I think one sees relatively little evidence of that. So my best guess, to provoke you, of what's behind all of this is that the largest phenomenon, by far, is the general clash between people's legitimate family desires and employers' current desire for high power and high intensity, that in the special case of science and engineering, there are issues of intrinsic aptitude, and particularly of the variability of aptitude, and that those considerations are reinforced by what are in fact lesser factors involving socialization and continuing discrimination.