A new study casts doubts on the perceived advantages of single-sex education.

Rebecca Bigler and Lise Eliot write in Slate.com that their research project shows that most successful single-sex schools are successful because of the backgrounds of the students, not the educational methods.

Additionally, they say the theory that boys and girls learn differently is wrong.

Thousands of studies comparing brain and behavioral function between adult men and women have found small to insignificant differences, and even smaller differences between boys and girls.

This is important, because much of the new single-gender K-12 pedagogy is based precisely on the idea that girls and boys need different—and often highly gender-stereotypic—learning environments to thrive. News reports describe girls’ classrooms in which the lights are low, the temperature is elevated, students are seated in small, collaborative clusters, and teachers are trained to speak gently and quietly as they conduct lessons involving fashion and wedding planning. Boys’ rooms, in some communities, are brightly lit, with the temperature turned down, the desks removed, and the boys engaged by loud, assertive teachers who keep them running relays and tossing balls during math lessons. Even preschools have followed the trend.