Washington ? For the first time in a generation, public schools have won broad freedom to teach boys and girls separately, stirring a new debate about equality in the classroom.

The Education Department has announced rules that will make it easier to create single-sex classes or schools, a plan that’s been expected for almost three years.

Published Wednesday and taking effect Nov. 24, the rules update the enforcement of Title IX, the landmark anti-discrimination law. The current language has stood since 1975.

The move comes as the value of same-sex education is in doubt. Research shows mixed results, as even the department’s own review says.

Yet Education Secretary Margaret Spellings said more parents deserve to have the option. The push began not with the White House, but rather with female senators of both parties.

“Research shows that some students may learn better in single-sex education environments,” Spellings said, careful not to offer an outright endorsement.

“The Department of Education is committed to giving communities more choices in how they go about offering varied learning environments,” she said.

The new federal rules may change how schools will look in the future.

Until now, single-sex classes have been allowed in only limited cases, such as gym classes and sex education classes.

The new rules will allow same-sex education anytime schools think it will improve students’ achievement, expand the diversity of courses or meet kids’ individual needs.

Enrollment must be voluntary. And any children excluded from the class must get a “substantially equal” coed class in the same subject, if not a separate single-sex class.

Districts also can offer an entire school for one gender without doing the same for the other gender, as long as there is a coed school that provides substantially the same thing.

About 240 public schools offer same-sex education in the United States, up from just three in 1995, according to the National Association for Single Sex Public Education.

Given new federal clarity, “There’s no question that we’re going to see very dramatic growth in the next year or two,” said Leonard Sax, the association’s executive director.