The following short summary is an excerpt from the National Association for Single-Sex Public Education
Single Sex Education Has Hidden Benefits Beyond Measurable Test Score Outcomes
Study after study has shown that simply putting girls and boys in separate classrooms will increase their scores on standardized tests. However, other studies prove that there may be some intangible benefits of single sex education as well.
Less Gender-Stereotyping
Girls in all-girls settings are more likely to take courses that are usually described as "male subjects" such as math and physics, according to the National Foundation for Educational Research study of 2002. Other studies have indicated that girls are more likely to participate in competitive sports in single-sex schools.
A University of Michigan study found that girls at single sex schools had fewer stereotypical ideas about what women can and cannot accomplish. They found that both male and female graduates of single sex schools are more likely to go on to a prestigious college and more likely to aspire to graduate or professional school.
British researchers interviewing middle school children found that boys at co-ed schools preferred math and science and showed little interest in drama or languages, but boys at all-boys schools liked these subjects equally.
A 2003 Australian study found that boys in single-sex schools tended to be more sensitive and polite, and less likely to develop "macho" attitudes. There was less stereotyping of boys as "geeks" or "jocks" in all-boys settings. Boys feel freer to pursue individual interests such as speech team, drama or music. Another study published in the Journal of Educational Psychology showed that boys in co-ed schools are more likely to believe that school is for "geeks" and "girls," than boys in all-boys schools. Boys in co-ed schools are also more likely to think that schools are female institutions run by women for the benefit of girls.
Margret Olafsdottir, an expert on single sex education, said, "mixed-sex schools support and increase old traditional roles," and single sex schools break down gender stereotypes. Girls become more competitive and boys become more collaborative.
More positive attitude toward Academics
Researchers writing in the Journal of Educational Psychology found that students in single-sex schools are more involved in learning and classroom activities and less preoccupied with social status and interactions than those in co-ed situations.
A major study at Cambridge University in London found that "single-sex education was a significant factor in establishing a school culture that raises educational achievement." These professors had expected to find that girls did better in single sex schools and boys did better in co-ed situations, because the girls' good behavior "brings up" boys. However, this was not the case. Boys did better in all-boys schools compared to their peers in co-ed ones. It was not the result of using girls as role models.