Gender-segregated education is making a comeback. Single-sex classrooms, long discouraged under Title IX, the federal law that prohibits gender discrimination in education, have been gaining prominence in recent years, especially in urban charter schools.
This fall, Los Angeles saw the launch of two all-girls' schools - the Girls' Academic Leadership Academy and the Girls' Athletic Leadership School (known by the perky acronyms, "GALA" and "GALS") - and Washington, D.C. district opened the Ron Brown College Preparatory High School for boys (or "Young Kings," as they refer to their students).
These schools join growing networks of inner-city single-sex public schools, such as the Urban Prep Academies for boys and the Young Women's Leadership Academies geared largely toward students of color.
Parents who choose single-sex schools do so for many reasons, but a major one is the belief that "boys and girls learn differently." Single-sex schools also claim to better tailor instruction to one or the other gender.
But brain and behavioral research does not support such beliefs. I study gender development in the brain, and my research has found no difference in the way boys and girls process information, learn, remember, read or do math.
Similarly, in-depth analysis of educational outcomes by Janet Hyde and colleagues at the University of Wisconsin has found scant evidence that single-sex schooling leads to better academic achievement.
On the other hand, research suggests that single-sex schooling may actually be harmful to children - by failing to prepare them for gender-integrated workplaces, shared leadership and equal partnership in families.
Gender segregation vs. racial segregation
Since the Supreme Court's 1954 ruling in Brown v. The Board of Education, the evidence has been clear that integration works for breaking down racial gaps in education.
The Supreme Court asserted that "separate educational facilities are inherently unequal."
The court's decision was based on social science evidence that separating and emphasizing differences between groups of people breeds stereotyping and discrimination.
Research by Rebecca Bigler at the University of Texas and Lynn Liben at Penn State University has further corroborated this. Their work shows that children are especially susceptible to feelings of favoritism about members of their own group, and to prejudice against those in contrasting groups.
The effect on children is the same whether adults divide them by race, gender or even t-shirt color.
Similarly, in classroom-based research Valerie Lee at the University of Michigan found the greatest expression of sexism in all-boys' schools.
She found such behavior was not limited to males - all-girls' campuses could also foster stereotyping and a type of "pernicious sexism," or dumbing-down of challenging material.
These findings led Lee to drop her initial advocacy for single-sex education and conclude that true gender equity could be achieved only through coeducation.
Harms of gender segregation
Other researchers have found that gender segregation inhibits opportunities for girls and boys to learn from each other.
For example, Carol Martin and her colleagues at Arizona State University have found that boys and girls, who differ only modestly in infancy, grow further apart in their attitudes, abilities and mutual understanding the more their environment distinguishes them from each other.
They called this the "gender segregation cycle."
Girls who grow up with brothers tend to be more interested in sports and building toys than girls without brothers.
For their part, boys have been found to develop better verbal ability and relational skills, and especially, achieve greater academic growth the more time and space they shared with girls.
Single-sex education eliminates such colearning opportunities and simultaneously increases discrimination and stereotyping.
For example, the ASU research team found that the more single-sex academic classes middle school students were enrolled in each day, the stronger was the belief of students that "boys are better in math" and "girls are better in language arts."
Some researchers even argue that gender segregation of children's sports has suppressed female athletic achievement.
The real reason for the STEM gender gap
In spite of such findings, schools like GALS and GALA are often promoted as good at preparing girls for predominantly male STEM fields such as engineering and computer science.
But there is no evidence for this. In fact, research finds that women who attend single-sex colleges or enroll in all-female science classes are not likelier to pursue and persist in STEM careers.
That's because the problem is not girls' academic ability or even their confidence in STEM subjects. It's the culture of gender segregation: Young women turn away from careers in engineering and computer science because they feel uncomfortable and unwelcome in overly male environments.
On the flip side, it is also cultural separation that inhibits many men from entering careers like nursing and teaching. In other words, gender segregation is the problem, not the solution for getting more women to advance in STEM and for more men to enter the HEAL professions -health, education, administration and literacy.
The question now is whether single-sex schooling will grow even more rapidly with the increasing support for charter schools and vouchers. Both are avenues of the "choice" movement that is deeply embraced by single-sex advocates.
Rather than separating boys and girls, many scholars argue schools should be moving in the opposite direction: fostering greater gender inclusion.
Public education could do more to teach boys and girls to work together, preparing them to better respect and support each other in their future jobs, families and civic lives.