Alan Borsuk & Amy Hetzner:

Reduce it to a yes or no answer – was it a good idea for you to be in a class that was all girls this year? Who says yes?
Twenty-six hands shoot into the air. A 27th joins with hesitation.
And that is every student present in this eighth-grade classroom at the Milwaukee Education Center, known as MEC, a Milwaukee Public Schools middle school in an old Schlitz Brewery building north of downtown.
Note the word public in the previous sentence.
Single-sex education has long been part of the private school scene in Milwaukee and nationwide. But single-sex classes in public schools are relatively new.
Still few in number, they are on the rise in much of the country, spurred by parent interest and rulings from the U.S. Department of Education in 2006 that, with limitations, gave the practice a green light. As of November, 366 public schools in the United States offered some or all of their classes separated by gender, according to the National Association for Single Sex Public Education.
The idea is controversial. Research is nowhere near a consensus on the results, and many people, including experts, have strong opinions on issues such as whether boys and girls learn in different ways and to what degree children behave differently without members of the other gender present.