OVER THE last decade, a new solution to the crisis in public education has emerged.

Recent neuroscience, the thinking goes, is finally showing that the brains of boys and girls are fundamentally different. Therefore, they must learn differently. So why not cast aside political correctness and build single-sex public schools? All-boys or all-girls classrooms should be an option for everyone, not just those whose families can pick up a private school tab.

Last week came a startling new report that should change the conversation. Writing in the prestigious journal Science, a team of eight scientists concluded that there is no well-designed research demonstrating that a single-sex learning environment improves academic performance. And the idea that anything in neuroscience argues for single sex education – that there are fundamentally different boy and girl brains – is dismissed in unusually stark language, as pseudoscience.

“There is really no basis for single sex-education,” says Diane Halpern, the report’s lead author, former president of the American Psychological Association and one of the world’s top experts on gender-based cognitive differences. “The research literature just does not support it.”

The report will hopefully serve as a brake on a movement that threatens to divert reformers’ attention from more fundamental issues. In 2002, there were about a dozen public schools offering single-gender classrooms, according to the National Association for Single Sex Public Education. Now there are more than 500 that teach boys and girls separately for at least part of the day. Dorchester’s Smith Leadership Academy is an example, and Massachusetts, like many states, is considering adding more.

But the Science report also draws attention to another problem: the cynical misuse of neuroscience. New tools are bringing great progress and thrilling insights. And yet, confronted with a brain scan, the public, and even scientists, are too quick to drop their critical faculties. The brain has become a brand.

For example, the authors of the Science report point to Dr. Leonard Sax, an author and paid school consultant who founded the National Association for Single Sex Public Education and who uses neuroscience arguments in support of his cause. His organization’s website devotes a page to research that cites a study showing substantial differences in the patterns of boys’ and girls’ physical brain development. (There is also a link to a video showing how the differences change over time.)

Then the website continues: “Why is this so important? Here’s why. If you teach the same subjects to girls and boys in the same way, then by the age of 12 or 14, you will have girls who think `geometry is tough’ and boys who believe `art and poetry are for girls.’ ”

It is an utterly convincing presentation, except that the study being cited does not show any difference in the functioning of children’s brains – the difference is purely physical – much less any difference in learning styles, or aptitude for geometry or poetry at any particular age. The study has no bearing on education. When I e-mailed Sax about this, he gave an evasive answer and then said, “When I cite brain research, I do so in an explanatory, not a prescriptive way.”

Obviously, there are other arguments in support of single sex education, and the neuro-nonsense spouted by Sax and others has no bearing on them.

Still, supporters of segregated classrooms now have a substantial academic record to confront. There are many hundreds of studies, of varying quality and with results across the spectrum. In the larger and better of these any apparent advantages tend to evaporate.

And we pay a price in segregating the sexes. Boys and girls learn from each other, and that prepares them for the world. Being separated cannot help but emphasize differences.

We need more experimentation in public schools, so perhaps there is a place for a small number of single sex classrooms or schools. But when they work, let’s at least be honest about the reason.

“We are not denying that there are some excellent single-sex schools,” says Halpern. “But their excellence does not come from the fact that they are single-sex.”