Any parent knows that little boys and little girls are different, but after that observation there’s plenty to argue about.

The latest dispute is between the Sanford School Department and the American Civil Liberties Union of Maine, which has lodged a complaint with an elementary school’s experiment in optional single-sex classrooms.

Teachers and administrators have observed that boys and girls learn differently, and there are children who suffer as a result. Some boys have trouble sitting through lessons and get in trouble for behavior that they can’t control. Some girls understand the material but are slow to raise their hands in a rambunctious environment.

Willard Elementary School offers an option that they say is popular with parents, teachers and students for single-sex sixth-grade classes. They say it helps children of both sexes, but the ACLU says it amounts to sex discrimination.

Deciding who is right depends on what “differences” the school is trying to accommodate. Most studies find that there is very little biological difference between boys and girls when it comes to learning. Certainly not enough to account for the differences that adults notice. But there are cultural differences that are imposed on children that can get in the way of a girl who wants to study science or a boy who wants to write poetry.

But it is a risky business to try to fight those stereotypes by separating boys and girls: The school is much more likely to reinforce them than break the mold, and there is evidence that suggests that the school is doing just that.

The ACLU charges that the program is built on gender stereotypes, not solid science. It describes a program where boys answer questions about professional football and are rewarded with a chance to do in-class exercise, while girls read the Portland Press Herald, talk about current events and sip cocoa.

This sounds like it shortchanges everyone. Girls should also be given the chance to blow off steam by doing exercise, and we strongly believe that everyone, regardless of gender, should read the Press Herald.

The great challenge for all schools is to help individual students do their best regardless of culturally imposed expectations. There is no reason to separate boys from girls to do that.