Single-sex classes began proliferating after the U.S. Education Department relaxed restrictions in 2006. With research showing boys, particularly minority boys, are graduating at lower rates than girls and faring worse on tests, plenty of schools were paying attention.
In 2002, only about a dozen schools were separating the sexes, according to the National Association for Single Sex Public Education, an advocacy group. Now, an estimated 500 public schools across the country offer some all-boy and all-girl classrooms.
