In today's life, some people think co-educational schools are better than single-sex schools for students, it means they believe if males and females study and grow together in future they can use their friendships in real-life and also problems to help each other. I absolutely agree with this statement and I will tell you why single-sex education has some negative points. On the one hand, when boys and girls were separated far from each other in school or any education system, they only see one gender which is the same as themselves. They do not have enough information about how the opposite gender thinks or behaves as the result, in the future they will face problems on their way. For example, Iran's education system is single-sex in school and high school and when students graduate from high school, in university most of them will have a problem with how to behave with the opposite gender and what they have to do when they are with each other. Therefore, many students ...