Could you imagine the outrage if any mainstream publication were to publish an article like this about any racial or ethnic group?

A new working paper from economists Victor Lavy of Hebrew University and Analía Schlosser of Princeton attempts to unpick the peer effects associated with gender, using data on nearly half a million students passing through Israel's school system in the 1990s. They compared consecutive year groups passing through the same school, figuring that if one year's group was 55 percent boys and the next year's was 55 percent girls, that difference was very likely to be random and thus susceptible to meaningful number crunching.

Their answer chimes perfectly with the conventional wisdom: Boys benefit from being in a classroom with girls, but girls do not benefit from being in a classroom with boys. What is interesting about Lavy and Schlosser's work is that it uses survey data provided by the children to work out what is causing the effects. The survey questions ask, for example, about violence in school, respect for teachers, classroom distractions, and relations among students.

Boys pollute the educational system, it seems, for a number of unmysterious reasons: They wear down teachers, disrupt classes, and ruin the atmosphere for everyone. And more boys are worse than fewer boys, not because they egg each other on but simply because more of them can cause more trouble in total.

One could, using the same sort of evidence, make similar claims regarding racially-mixed educations. A look at disciplinary records and academic performance data would likely bear that out. But is that a basis for advocating a return to racially segregated education? No -- and indeed, it has been the basis for arguing that there is a crisis in schools and that more resources need to be devoted to making sure that minorities do better in school and that steps be taken to end the "bias" in discipline.

And then there is this little gem at the end.

A social planner might thus conclude that all education should be single-sex. The difficulty is to combine this perspective with the principle of parental choice. I have the answer: a congestion-charge-style tax on parents who insist on polluting girls' education with their testosterone-fuelled little monsters. The money could go toward hiring extra teachers—and riot police.

Again, could you imagine the outrage if someone were to write an argument arguing that there should be a congestion-charge-style tax on parents who insist on polluting whites' education with their Spanish and Ebonics speaking little gang-bangers? But in this case, the silence will be deafening.

I guess you just have to choose the right target for your bigotry.