Chicago’s Urban Prep Academy boasts of some remarkable statistics: In 2006, only 4 percent of the inaugural freshman class at the school — a public all-male, predominantly black high school located in one of the city’s most beleaguered neighborhoods — could read at grade level. Yet in May, 100 percent of the school’s seniors had been accepted to four-year colleges or universities, many on full academic scholarships.

Many education experts attribute Urban Prep’s success to its eight-hour school day, intense focus on college and double periods of English. But some credit another factor: the school’s single-sex format and use of teaching methods that are engaging to young men.

Single-sex education has been growing in popularity since the 2002 No Child Left Behind Act was passed, allowing local educational agencies to use “Innovative Programs” funds to support same-gender schools and classrooms “consistent with existing law.” The U.S. Department of Education loosened its Title IX regulation in 2006 to diminish prohibitions on single-sex education. Today, Urban Prep is among the nation’s 95 single-sex public schools, according to the National Association for Single Sex Public Education (NASSPE). In addition, more than 445 public coed schools offer single-sex classrooms.

While simply separating boys and girls doesn’t guarantee success, schools that use best practices for gender-specific teaching may be more successful at teaching to boys’ and girls’ strengths, says NASSPE Executive Director Leonard Sax, MD, PhD, a psychologist and family physician.

“What we’re doing right now — pretending that gender doesn’t matter — is not working,” he says. “We are losing ground.”

Yet many experts say much of the success of single-sex schools stems from a demanding curriculum and a focus on extracurricular activities — gains that would have been seen regardless of whether the opposite sex was in attendance.

“You can’t simply attribute the outcome to the fact that they’re single-sex when you’re changing lots of other things at the same time,” says Diane F. Halpern, PhD, a psychology professor at Claremont McKenna College who has served as an expert witness in several federal court cases on single-sex education in public schools. Halpern and several other psychologists have also joined together to create the American Council for CoEducational Schooling (ACCES), a nonprofit research organization that is examining the science and implications of organizing classrooms on the basis of students’ biological sex.

Coeducation advocates and researchers also report that segregating students by gender — be it via entire schools or simply classrooms — can lead to greater gender discrimination and make it harder for students to deal with the other sex later in life.

“School is preparation for adult life,” says Halpern, a former APA president. “How can boys and girls learn how to interact as equals in the workplace if they have no experience interacting as equals in school?”

What the two sides can agree on, however, is that every child is unique and deserves an education that uses evidence-based teaching approaches to meet their particular needs.

“What’s particularly important is presenting school structures and educational opportunities in ways that can appeal to and draw on individuals’ interests, aptitudes and motivations as opposed to their category membership,” says Pennsylvania State University psychologist Lynn Liben, PhD, who studies how stereotypes affect children’s educational and occupational choices.

Learning differences

Single-sex education advocates often point to brain differences as evidence for the benefits of separating girls from boys in the classroom.

According to a 2007 longitudinal pediatric neuroimaging study led by a team of neuroscientists from the National Institute of Mental Health, various brain regions develop in a different sequence and tempo in girls compared with boys (NeuroImage, Vol. 36, No. 4). Using 829 brain scans gathered over two years from 387 subjects from 3 to 27 years old, researchers found several remarkable differences. The occipital lobe, for example — the one most associated with visual processing — shows rapid development in girls 6 to 10 years old, while boys show the largest growth in this region after 14 years old. Other studies have also shown disparities in language processing between the sexes, concluding that the language areas of the brain in many 5-year-old boys look similar to that of many 3-year-old girls (Developmental Neuropsychology, Vol. 16, No. 3).

“Timing is everything, in education as in many other fields,” says Sax, author of several books on the science of sex differences, including “Girls on the Edge: The Four Factors Driving the New Crisis for Girls” (Basic Books, 2010). “It’s not enough to teach well; you have to teach well to kids who are developmentally ripe for learning.” For example, asking 5-year-old boys to sit still, be quiet and pay attention is often not developmentally appropriate for them, but there are other ways to teach boys to read that don’t require boys to sit still and be quiet, he says.

“In some of the most effective boys’ classrooms for 5-year-old boys, one boy is standing and making buzzing noises, while another is lying on the floor, and another is twirling,” Sax says. “But all of them are learning to read.”

Coeducation advocates agree that there are some small physiological differences in male and female brains. But they also say there’s a lack of evidence that these differences matter to learning at the individual level. For example, a meta-analysis of 242 studies conducted between 1990 and 2007 — published in the November 2010 Psychological Bulletin (Vol. 136, No. 6) — examines gender differences in math performance and finds that girls perform as well in the subject as boys.

“The great majority of these girls and boys did their learning in coeducational classrooms,” say the article’s authors, who include University of Wisconsin–Madison psychologist Janet Hyde, PhD.

Both Sax and psychologist Lisa Damour, PhD, who co-directs the Center for Research on Girls at Laurel School, an independent girls’ day school in Shaker Heights, Ohio, agree that gender differences can be overblown.

“We really shouldn’t be developing curricula or approaches to teaching that don’t account for the fact that a lot of girls in a girls’ school are going to think and act like boys and the other way around,” Damour says. The benefit of single-sex schools, however, is that they offer the dynamic of having only one sex in the classroom at a time, creating opportunities that don’t exist in the coed classroom, she says. Teachers, therefore, can use strategies in the all-girls classroom and in the all-boys classroom that don’t work as well — or don’t work at all — in the coed classroom. For example, despite performing as well as boys in math courses, girls often doubt their ability to develop their math skills when faced with difficult material, according to research by Stanford University psychologist Carol Dweck, PhD. This mindset appears to contribute to substantial gender gaps in math scores that emerge during and after middle school, Damour says, so to help students learn that ability can be improved through effort, teachers at Laurel School provide grade-level appropriate neuroscience lessons about how the brain creates new connections when it’s learning challenging material. Teachers also draw parallels between brain and muscle development, reminding struggling students that the mind strengthens with effort, and that practice makes the work easier.

“We can focus on the needs of girls all day long and never have to give a second thought to whether we’re giving someone else short shrift,” Damour says.

While these types of teaching approaches may be thought to improve grades, test scores and college acceptance rates, there’s little empirical evidence showing that sex-segregated classes improve educational outcomes. A 2005 U.S. Department of Education comparison of same-sex and coeducational schools found a dearth of quality studies examining academic benefits and concluded that the results are mixed and not conclusive enough for the department to endorse single-sex education.

The problem, many experts say, is that it’s nearly impossible to compare apples to apples when it comes to single-sex versus coeducation. Most research on single-sex education has been done with private schools, not on single-sex classes in U.S. public schools. In addition, it’s rare for any studies on the topic to use random assignment. Even if they are public — and not charter or magnet — schools often also make academic changes when they switch to a single-sex format, making it hard to attribute gains or falls to any one measure.

“The entire literature on single-sex schooling is confounded by the possible presence of student and school selection biases,” says Rebecca S. Bigler, PhD, a psychology professor at the University of Texas at Austin who studies gender role development and racial stereotyping. “You can’t conclude a thing about single-sex schooling if you don’t check for and control those two potential biases.” Research on single-sex education is also complicated by the legal requirement that assignment to single-sex classes must be completely voluntary.

Bigler adds, however, that as public single-sex schools increasingly begin to offer admission based on a lottery system, opportunities for more effective studies on the topic should emerge. Bigler is co-editing a special issue of the journal Sex Roles slated for this year that will include several studies on single-sex schooling that have controlled for selection biases.

Rewriting gender stereotypes?

Mixed academic outcomes aren’t the only reason the debate on single-sex education continues. The research is also inconsistent on whether single-sex education can reduce gender stereotypes. Sax and other advocates say that single-sex education has been shown to broaden students’ horizons and encourage them to explore their own strengths and interests without feeling constrained by gender stereotypes. A 2003 University of Virginia study led by educational psychologist Abigail Norfleet James, PhD, for example, found that boys who attended single-sex schools were more than twice as likely to pursue interests in subjects such as art, music, drama and foreign languages compared with boys of comparable ability who attended coed schools (Psychology of Men and Masculinity, Vol. 4, No. 2).

Although she has no research on it, Damour adds that at Laurel students seem much more focused on school than on the other typical concerns of adolescent girls. “During the school day, they’re not distracted by the cute boy down the hall, and they’re not worrying about how they look or what they’re wearing,” Damour says. “I never felt that relaxed in the hallway of my public coed high school.”

Yet other experts suggest that segregating students by sex can actually increase gender stereotyping. A study by Liben and her graduate student Lacey Hilliard found that highlighting gender promotes stereotyped views in children as young as 3. The researchers evaluated 57 3- to 5-year-olds at two similar preschools over a two-week period. In one set of classrooms, teachers were asked to avoid making divisions by sex, and in the other, teachers were asked to use gendered language and divisions, such as lining children up by gender and asking boys and girls to post their work on separate bulletin boards. At the end of two weeks, the researchers examined the degree to which children endorsed cultural gender stereotypes — asking the children, for example, whether only girls should play with baby dolls and assessing their interest in playing with children of each sex. They found that children in the classrooms in which teachers avoided characterizations by sex showed no change in responses or behaviors. However, children in the other classrooms showed increases in stereotyped attitudes and decreases in their interest in playing with children of the other sex. They also were observed to play less with children of the other sex. The study appears in the November/December Child Development (Vol. 81, No. 6).

These results suggest that children are strongly affected when the surrounding environment makes gender divisions explicit, even though they are already well aware of gender, Liben says. “These effects are likely to have profound impacts on the kinds of learning experiences and personal relationships kids have down the line.”

Others point to the long-term effects of gender stereotyping on school infrastructure and curriculum as a down side of separating boys and girls in the classroom. Educational psychologist Sue Klein, EdD, education equity director with the Feminist Majority Foundation, a non-profit advocacy organization dedicated to women’s equality, reproductive health and nonviolence, says that separate rarely means equal in public schools that make the switch to a single-sex format. Often, Klein says, women receive fewer quality resources, and many single-sex schools and classrooms exaggerate and encourage sex stereotypes by emphasizing competition and aggression among boys and passivity among girls or by setting the expectation that boys are not good at writing. In addition, while many schools justify their separation of boys and girls using the 2006 updated Title IX regulation, many of the sex-segregated public education programs are illegal because parents aren’t provided with a coeducational choice for their child or the links between the education goal and the single-sex program aren’t shown, she says.

“We need to understand this whole area better, but I think we know enough now that this is not a good way to spend our country’s limited education dollars,” Klein says.

It’s about choice

The bottom line, Sax says, is that most single-sex education advocates don’t believe that single-sex education is best for every child.

“There is a great variation among girls and a great variation among boys and for that reason, choice is a good thing,” says Sax. “One size does not fit all.”

Effective teaching often depends on getting children engaged and excited about learning the material, says Florida State University psychology professor Roy F. Baumeister, PhD, and for that, each teacher has to work with each child’s motivations, interests and preferences.

“America’s schools have many problems, and there is no one solution,” says Baumeister, author of “Is There Anything Good About Men?” (Oxford, 2010). “But if there is one suggestion that is likely to yield solutions, it is to allow experiments.”

So, as the research continues to explore the benefits of coed and single-sex schools, Baumeister suggests letting parents decide which option is best suited to a child’s individual needs and talents.

“Many boys and girls do fine with coed schools, but some do better in same-sex schools,” Baumeister says. “Society can benefit from choice and diversity, so let’s offer options.”

ACCES researchers, on the other hand, argue that segregation is very seldom a beneficial form of “choice” and that fostering diversity within schools, rather than across schools, is the best option. Psychologists and education experts are likely to hear much more about this controversial issue as researchers on both sides continue their work.

Amy Novotney is a writer in Chicago.