Sex-segregated primary and secondary education fails to improve educational outcomes, such as test scores and college admission rates, and can increase sex stereotyping, according to a Sept. 23 article in the "Education Forum" of the journal Science.

"Contrary to many people's beliefs, single-sex schooling is not supported by serious scientific research and may actually be harmful to children's social development," says co-author Lise Eliot, PhD, a neuroscience professor at Rosalind Franklin University of Medicine and Science in Chicago. The article's first author is former APA President Diane Halpern, PhD, a psychology professor at Claremont McKenna College in California.

The paper — written by eight social scientists who founded the nonprofit American Council for CoEducational Schooling — cites several large reviews published over the last few years, all reporting little difference between single and mixed-sex academic outcomes.

The perception of the superiority of single-sex education comes from "an historical accident," Eliot says — namely, that the best, most expensive private schools in the United States, England and elsewhere were traditionally single sex. But studies now show that benefits of single-sex education disappear when researchers control for demographics and school quality, she says.

The paper also contradicts claims from single-sex proponents that girls and boys learn differently because of innate brain differences. Some researchers assert that, for example, boys respond to confrontational, aggressive teaching styles while girls should be treated more gently by educators. But these conclusions come from "obscure and isolated findings about brain maturation, hearing, vision, and temperature sensitivity," the authors say, and are recognized by most scientists as "pseudoscience."

The report also says that single-sex education may increase gender-stereotypical behavior among children, citing studies finding that both girls and boys behave in more sex-typed ways when they interact primarily with members of their own gender.

Last, the authors address some educators' and parents' requests that students simply be given a choice between single and mixed-sex classes. "But such choice is not without its costs," Eliot says. "If a school district is going out of its way to provide single-sex education, what other truly evidence-based enrichment opportunities is it passing up?"

—M.L. Phillips