As schools examine how to increase student achievement, single-gender classes increasingly are being viewed as a possible way to improve performance.

St. Michael's Episcopal Day School is an example. Noting that boys and girls learn differently, school officials at the co-ed campus in Carmichael this year separated by gender its seventh-and eighth-grade science, writing, math, Spanish, and computer classes.

Mary Heise, assistant head of the school, said the school is focused on boys' and girls' learning styles, such as linguistic, spatial and logical.

"We just want to do the best job we can possibly do in meeting the needs of individual students," Heise said.

Research is limited regarding the benefits of single-gender classes, but various schools, including public campuses, periodically have separated individual classes by gender.

In 1997, California became the first state to implement single-sex public education on a large scale, according to state documents. Under legislation and funding from then-Gov. Pete Wilson's administration, six school districts opened single-gender academy pilot programs for boys and girls.

The program lasted until 1999 and did not require an evaluation of its performance, said Karen Humphrey, an administrator with the state Department of Education and former single-sex academies coordinator.

Each school district was required to evaluate itself, Humphrey said. Her department requested a statewide evaluation, but it was never funded or approved.

"The program was believed to be an effective structure for some kids in some circumstances," Humphrey said.

The academies generally targeted middle and early high school students considered at risk, including low-achievers and students with behavior problems. At least one pilot program served mostly Latino and African American populations, who they believed would do better in single-sex settings.

However, lack of support for gender-based reform - coupled with competing demands for resources - led to academies, according the researchers.

Today, the state has two single-gender public school programs. The San Francisco 49ers Academy in East Palo Alto, for grades six through eight, is the only remaining pilot academy. The Jefferson Leadership Academies in Long Beach opened in 1999 and were not part of the pilot program.

Most educators viewed the single-gender schooling arrangement as a way to decrease distractions among boys and girls to improve students' self-esteem, according to an executive summary of the pilot program.

The Rev. Jesse Vaughan, headmaster at St. Michael's, said officials have noticed that eighth-grade boys have had lower citizenship grades since the school piloted the new instructional program.

"It takes more time (for boys) to settle down," said Vaughan, adding that the school plans to do a formal assessment.

"Girls would organize the boys, telling them it's time to get started, but now they are left to their own devices," Vaughan said. "Girls seem more prepared."

St. Michael's has 250 students in preschool through eighth grade, with one class per grade.

Many of the students go on to single-sex private schools, such as Jesuit High School for boys and Loretto or St. Francis high schools for girls.

Vaughan said lower grades are exempted from single-gender classes, because co-ed interaction is beneficial for students' development.

In a co-ed seventh-grade history class recently, students worked in groups, discussing motivations for exploration, such as breaking up monopolies, conversion to Christianity, and balance of trade. Same-gender groups, for the most part, seemed more involved in the lesson, while co-ed groups seemed less focused on the classwork. In one group, a boy was standing up and talking and a girl was laughing.

Psychologist Leonard Sax, executive director for the National Association for Single Sex Public Education, said boys and girls learn, interact and make decisions differently.

Some St. Michael's students have noticed the difference in their core classes and prefer a co-ed model to single-sex.

"I don't like it that much," seventh-grader Nick Tyler said of his all-boy classes. "It's louder."