i'm always mildly flabbergasted this isn't common sense --- we have all met men and women right?If science were just "common sense", we'd still believe in the impetus theory [1]. Plus, personal experience tends to suffer from all kinds of confirmation bias.
we can also point at the related psychological issues of transgender people...
Looking at transgender people is indeed interesting, if not the way you think it is. In particular, how the same person gets treated completely differently based on which gender he or she is perceived as [2]. E.g.:
"After he underwent a sex change nine years ago at the age of 42, Barres recalled, another scientist who was unaware of it was heard to say, 'Ben Barres gave a great seminar today, but then his work is much better than his sister's.'" (Ben and his "sister" are one and the same person, of course.)
sure this might not apply to precisely this, but afaik medical professionals believe that there are gender differences beyond naive physiology and treat their patients accordingly - when they assumed the differences were merely cultural they caused well documented suffering.
And how do you conclude that any such difference reflects a higher aptitude of men for STEM subjects instead of a higher aptitude of women for STEM subjects?
[1] http://en.wikipedia.org/wiki/Theory_of_impetus
[2] http://www.washingtonpost.com/wp-dyn/content/article/2006/07...