This will put a Cat amongst the Pigeons...

From Opinion Journal :

Evolutionary biologists have some theories that feed into an explanation for the disparity. In primitive societies, men did the hunting, which often took them far from home. Males with the ability to recognize landscapes from different orientations and thereby find their way back had a survival advantage. Men who could process trajectories in three dimensions--the trajectory, say, of a spear thrown at an edible mammal--also had a survival advantage. Women did the gathering. Those who could distinguish among complex arrays of vegetation, remembering which were the poisonous plants and which the nourishing ones, also had a survival advantage. Thus the logic for explaining why men should have developed elevated three-dimensional visuospatial skills and women an elevated ability to remember objects and their relative locations--differences that show up in specialized tests today.

Perhaps this is a just-so story. Why not instead attribute the results of these tests to socialization? Enter the neuroscientists. It has been known for years that even after adjusting for body size, men have larger brains than women. Yet most psychometricians conclude that men and women have the same mean IQ (although debate on this issue is growing). One hypothesis for explaining this paradox is that three-dimensional processing absorbs the extra male capacity. In the past few years, magnetic-resonance imaging has refined the evidence for this hypothesis, revealing that parts of the brain's parietal cortex associated with space perception are proportionally bigger in men than in women.
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Women have their own cognitive advantages over men, many of them involving verbal fluency and interpersonal skills. If this were a comprehensive survey, detailing those advantages would take up as much space as I have devoted to a particular male advantage. But, sticking with my restricted topic, I will move to another aspect of male-female differences that bears on accomplishment at the highest levels of the arts and sciences: motherhood.

Regarding women, men and babies, the technical literature is as unambiguous as everyday experience would lead one to suppose. As a rule, the experience of parenthood is more profoundly life-altering for women than for men. Nor is there anything unique about humans in this regard. Mammalian reproduction generally involves much higher levels of maternal than paternal investment in the raising of children. Among humans, extensive empirical study has demonstrated that women are more attracted to children than are men, respond to them more intensely on an emotional level, and get more and different kinds of satisfactions from nurturing them. Many of these behavioral differences have been linked with biochemical differences between men and women.

Thus, for reasons embedded in the biochemistry and neurophysiology of being female, many women with the cognitive skills for achievement at the highest level also have something else they want to do in life: have a baby. In the arts and sciences, 40 is the mean age at which peak accomplishment occurs, preceded by years of intense effort mastering the discipline in question. These are precisely the years during which most women must bear children if they are to bear them at all.

Among women who have become mothers, the possibilities for high-level accomplishment in the arts and sciences shrink because, for innate reasons, the distractions of parenthood are greater.
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I have omitted perhaps the most obvious reason why men and women differ at the highest levels of accomplishment: Men take more risks, are more competitive and are more aggressive than women. The word testosterone may come to mind, and appropriately. Much technical literature documents the hormonal basis of personality differences that bear on sex differences in extreme and venturesome effort, and hence in extremes of accomplishment--and that bear as well on the male propensity to produce an overwhelming proportion of the world's crime and approximately 100% of its wars.

But this is just one more of the ways in which science is demonstrating that men and women are really and truly different, a fact so obvious that only intellectuals could ever have thought otherwise.

Now that the Radical Feminists are going ballistic, I'll quote another part of the article, and this one is the key:

Here are three crucial points to keep in mind as we go along:

1. The differences I discuss involve means and distributions. In all cases, the variation within groups is greater than the variation between groups. On psychological and cognitive dimensions, some members of both sexes and all races fall everywhere along the range. One implication of this is that genius does not come in one color or sex, and neither does any other human ability. Another is that a few minutes of conversation with individuals you meet will tell you much more about them than their group membership does.

2. Covering both sex differences and race differences in a single nontechnical article, I have had to leave out much. I urge that readers with questions consult the fully annotated version of this essay, which includes extensive supplementary material; it is available here at Commentary's Web site.

3. The concepts of "inferiority" and "superiority" are inappropriate to group comparisons. On most specific human attributes, it is possible to specify a continuum running from "low" to "high," but the results cannot be combined into a score running from "bad" to "good." What is the best score on a continuum measuring aggressiveness? What is the relative importance of verbal skills versus, say, compassion? Of spatial skills versus industriousness? The aggregate excellences and shortcomings of human groups do not lend themselves to simple comparisons. That is why the members of just about every group can so easily conclude that they are God's chosen people. All of us use the weighting system that favors our group's strengths.

Obvious, yes, but how many people will ignore that and call for the author's public execution?

Especially since the author then goes on to say this :

Turning to race, we must begin with the fraught question of whether it even exists, or whether it is instead a social construct. The Harvard geneticist Richard Lewontin originated the idea of race as a social construct in 1972, arguing that the genetic differences across races were so trivial that no scientist working exclusively with genetic data would sort people into blacks, whites or Asians. In his words, "racial classification is now seen to be of virtually no genetic or taxonomic significance."

Mr. Lewontin's position, which quickly became a tenet of political correctness, carried with it a potential means of being falsified. If he was correct, then a statistical analysis of genetic markers would not produce clusters corresponding to common racial labels.

In the past few years, that test has become feasible, and now we know that Mr. Lewontin was wrong. Several analyses have confirmed the genetic reality of group identities going under the label of race or ethnicity. In the most recent, published this year, all but five of the 3,636 subjects fell into the cluster of genetic markers corresponding to their self-identified ethnic group. When a statistical procedure, blind to physical characteristics and working exclusively with genetic information, classifies 99.9% of the individuals in a large sample in the same way they classify themselves, it is hard to argue that race is imaginary.

Homo sapiens actually falls into many more interesting groups than the bulky ones known as "races." As new findings appear almost weekly, it seems increasingly likely that we are just at the beginning of a process that will identify all sorts of genetic differences among groups, whether the groups being compared are Nigerian blacks and Kenyan blacks, lawyers and engineers, or Episcopalians and Baptists. At the moment, the differences that are obviously genetic involve diseases (Ashkenazi Jews and Tay-Sachs disease, black Africans and sickle-cell anemia, Swedes and hemochromatosis). As time goes on, we may yet come to understand better why, say, Italians are more vivacious than Scots.

Here we have a vexatious problem. Junk Pseudo-Science has been used as a justification for all sorts of atrocities and injustices. So what happenes when, being as objective as we possibly can, we come across some results that we don't like, that can and will be misconstrued by the ignorant and bigotted to justify great Evil? Do we stay silent and "Politically Correct", judging that we have a responsibility to actively prevent such happenings? Or do we abdicate our social responsibility in favour of telling the Truth as it has been revealed to us by experiment and objective measurement?

I'm torn between the two. But on balance, monster of arrogance and ego that I am, I don't feel confident enough in my own righteousness to do anything other than to call em how I sees em. If I have a duty of care, a responsibility, it is to be as objective as possible, and ignore whether the results I get are in accordance with what I think they should be, or otherwise. They are what they are. By all means cross-check and try to eliminate my own cultural bias and prejudice, and state many disclaimers as to why I may be in error. But publish the results, and be damned. As I'm sure the author, Charles Murray, will be.