Sorry I am just getting back to this now. It has been a very busy end of school year.
Aside from the learning differences, there are other reasons why I prefer single gender schools for my kids.
1. The primary reason is less pressure. In the mixed school where I teach, there always seems to be some drama about who is dating who, why he didn't say "hi" in the hallway, etc. In other words, major distractions. Also, the boys and girls both seem to have this pressure to sit with the other person at lunch instead of with friends. If they don't, the other half of the couple spends the rest of the day analyzing the action of the other. Sigh. Also, most girls I know at all girl schools tend to wake up, throw on the uniform, and go. No spending hours on hair and make up to impress some guy. Same thing for the boys.
2. Leadership. Both boys and girls benefit when they can take leadership roles. It has been proven in studies that girls tend to take more leadership roles in all girl schools. I have to say that in many schools today, girls tend to run things like student council, etc. So maybe now it benefits the boys to be in an all boy school.
3. Sports. In all girl schools, the sports for girls are more highly valued. As the mother of a girl who wants to play high school basketball, I like this. When I taught at an all girls school, we had pep rallies for all the sports- volleyball, basketball, softball, etc. The cheerleaders cheered at all the sports for all the girls.. At the mixed gender school it is ALL ABOUT FOOTBALL. I mean, all about football. It rules and everyone knows it.
I have to add that I have three kids- 1 boy, 2 girls. So the socialization issue and being around the opposite sex is not really an issue for my kids; they were in mixed gender schools until 8th grade, and they still keep in contact with members of the opposite sex. Also, the older ones are involved in CYO, and there is plenty of opportunity for socialization there. The boys' and girls' school have dances and mixers, as well as joint-service projects- these are all ways to interact with others.
Finally, it is all about making the right decision for YOUR kids. My kids have known since K that their high schools would be single gender schools and the idea of anything else would seem odd to them.