Single-Gender Schools

In observance of student-teacher interaction, studies have shown that boys are called out 8 times as often as girls; girls had to raise their hands to talk, and were expected to be extremely polite whereas boys didn't, they would even talk without permission and the teacher would praise them for answering! Thus boys and girls are treated differently in co-educational settings, which is why they would both benefit from  single gender classrooms.
Personally, I have studied in a single gender religious school, and it was very important for me as a girl to study in such a school. First because I wanted to learn more about my religion, yet in a lot of situations a girl might be shy to ask the teacher questions that are kind of personal if there were boys in class, so we used to feel comfortable and confident to ask personal questions because we knew most of us-girls- were passing through the same situation, or might eventually pass through it. Second, we felt comfortable sharing our way of thinking without being mocked or thought of as "girlish". Finally, we were treated very well and respected by all teachers, and even the administration, they would all treat us as their daughters, they didn't use offensive language with us even when we did something wrong, they would rather sit with us, advice us, and show us our mistakes; whereas if there were boys with us in the class there might have been a lot of shouting or even offensive talk. 
Personally, as a girls, I am 100% with single gender schools.