Which one is better,single-sex or co-educational schools?

co-educational schools better!!
~ more similar to real world
~ get a experience in communication with people in different sex
~ different sex have different strong point which we can learn!!
~ different point of view we can know

I think co-educational schools are better because you can meet more friends and learn from different people,not just a single-sex.Otherwise,you need to communicate with girls or boys when you grow up,right?