Read other letters about this article
Whether or not Larry Summers' claims were true about girls and math (I have not fact checked them), let's at least get them right-- your link to a former article does not note that its claims are bogus (as the letters in response point out-- you should read them and stop linking to that bogus article or refute the responses such as this one). What Summers claimed was that girls' math abilities had less variance. He did not say they had a lower mean or median.
And as to pay going down when girls flock to a major-- that is what happens when the largest demographic in college flock to a major. Lets not confuse correlation and causation. One hypothesis is sexism, and one is supply and demand. Assuming it is sexism is just as vapid as paying a woman lower because she is a woman, and that type of pseudo-science should be on Fox, not Salon.