The researcher from the university of Utrecht in The Netherlands analyzed how well boys can read, and apparently they perform better when their reading skills are tested. The sociologist looked at more than 200,000 test results. More than 8,000 schools participated.
Boys who were in a learning environment with more girls than boys, about 60 percent vs 40 percent, did better. Since reading skills are tightly linked to how a student performs in other subjects you can conclude that boys will perform better in school when they have more female classmates than male ones.
The reason could be that girls are more motivated and concentrate better, and this attitude is positively contagious.
So, perhaps this is more proof that we are indeed the average of the 5 people we spend the most time with.
You can take a look at the study here.