Here's what I'm curious about (and I'll admit I haven't read much on the topic): aren't most of the studies that show that girls do better in math in a same-sex environment done in a mixed-level class? I'm wondering how they might apply to HG girls specifically? or if it's really the upper-mid section of girls that are benefiting the most?
I read in the not so distant past a paper done on the effects of separating the sexes for math. It was in a compendium of Gifted Child Today articles on math. The article by Stutler. When they separated the girls from the boys interesting things happened. The girls started to relax in class and they started asking deeper questions about the topic before they started working on the problems. The boys didn't even notice there weren't any girls in the class (although it's the first thing the girls noticed). The boys asked almost no questions before they started answering problems, and only asked them if they ran into trouble. The girl's grades improved significantly (compared to their grades the year before) by the end of the semester; the boys grades declined dramatically. I wish I had the article here, because the difference in grades was eye popping. My memory is rotten-- but I think the girls had 5x as many A's as did the boys. These were gifted students.