The approach is based on the much-debated yet increasingly popular notion that girls and boys are hard-wired to learn differently and that they will be more successful if classes are designed for their particular needs.

With encouragement from the federal government, single-sex classes that have long been a hallmark of private schools are multiplying in public schools in the Washington area and elsewhere. By next fall, about 500 public schools nationwide will offer single-sex classes, according to the National Association for Single Sex Public Education, based in Montgomery County. That’s up from a handful a decade ago. The approach is especially attractive to some struggling schools in the market for low-cost reform.
More Schools Trying Separation of the Sexes – washingtonpost.com

It makes good sense, so I’m sure there will be a groundswell of disapproval.