Whose brain is better -- his or hers?

John at EclectEcon quotes and links an interview with Dr. Paul Irwing regarding the difference in cognitive abilities of men and women:

All the research I've done points to a gender difference in general cognitive ability. There is a mean difference of about five IQ points. The further you go up the distribution the more and more skewed it becomes. There are twice as many men with an IQ of 120-plus as there are women, there are 30 times the number of men with an IQ of 170-plus as there are women.

I'd love to see Irwing's test data... especially, though, I'd love to see similar cognitive tests performed on pre-school kids, as compared with college students. Doing a comparative analysis of young to older subjects might -- or might not -- indicate where education/culture influences the application of intellect.

We've already seen, in a number of fairly reputable studies, that girls have an inborn adeptness with language (verbal and nonverbal) for which boys have drawn the short straw. Boys, on the other hand, have a more overt, exploratory (read: aggressive... wink wink you wouldn't hit a girl like me, wouldja?) nature and the mathematical bent. These are tendencies which likely have always had some root in necessity, in survival of the species in the wild. However, they are also tendencies which can, with proper upbringing, be overcome.

That is to say, a boy may learn to use language as an art form to become the next Walt Whitman, and a girl may learn to be an astrophysicist. They are not sex-exclusive brain abilities, but merely trends and tendencies in higher brain function.

So, the questions I have to ask are as follows:

1. Do toddlers show comparable sex-based differences in cognitive testing as their adult counterparts?
2. If yes, should this be cause for alarm (shouldn't we accept that genetics might have had a useful function, at least originally, and say "vive la difference!")?
   
3. If no, precisely how is it that our culture/education fails us all, and how can we safely and effectively fix the fault?

I'm not terribly worried about this, for myself. Aside from being nuts, I'm smart, dammit, and comfortably so. I score in the upper-130s on IQ tests. And I'm the slow one in my family -- both my younger sisters score higher than I, as does my older brother. The difference, however, is only about 5 points -- and one of my sisters is at the top. We are, apparently, an unusual family.

There seems to be a fear that the XY/XX difference is writ in stone as the only definition of what we can become. If there are genuine innate partitions, I believe we ought to take advantage of them. They're built-in, so welcome that reality, and use them as support walls for the structure of our souls and minds.

If the divisions are not genetic, but cultivated over time via repetition of observations and behaviors, so be it. Culture is a large part of what we are, and what we will become. Changes in culture -- like changes in biology -- need time to develop safely.

Meanwhile, don't panic. Whatever the outcome, we are all still human beings, aren't we?