I have a different answer. Single-gender schools make the class act more like a team. When the two genders work together, problems are less likely to arise. This means that teachers can spend more time teaching students the theories that will help them succeed in their new careers. The reason why single gender schools are better than multi-sex schools is because of how each gender works together in order to complete a project. Two people who don't know each other very well can quickly become the subject of a sexual relationship when they are given the same task at the same time. This is very different from being forced to work with a group of people and knowing each person's personalities.

Single-gender schools provide more opportunities for the students to expand their knowledge about the world and each other. There is also less danger for the students if one of the students decides to have sex during class. The teacher will have more on-the-job training and experience in dealing with issues of sexual abuse, which they wouldn't if they were teaching a group of students. Single-gender schools also allow teachers to focus on the people who are in charge of teaching the classes instead of the students, which is especially beneficial to those people who have trouble motivating students.