The past decade has witnessed a growing number of experiments in sex-segregated public education. Although the bloom may be off the rose — districts in Louisiana, Pennsylvania and Wisconsin recently decided to end, or not commence, such plans — they are scarcely moribund, despite attacks by the American Civil Liberties Union and resistance from mainstream feminist groups. Indeed, in 2011-12, more than 500 schools in 40 states are either wholly single-sex or furnish single-sex classrooms. Some proponents claim that these programs are needed to remedy the ills of urban educational systems.

Taxpayer funding for such instruction raises a plethora of legal issues, which have largely come to the fore since 2006 when the U.S. Department of Education (DOE) promulgated new Title IX regulations adopting a more welcoming approach to such initiatives. The DOE issued them in response to No Child Left Behind’s encouragement of “innovative assistance programs,” including ones “to provide same-gender schools and classrooms” — “consistent,” however, “with applicable law.” This cautionary caveat has proven unhelpful on the statutory and administrative fronts, where text and legislative history are murky and judicial interpretation scant and sometimes outdated. Moreover, in the one U.S. Supreme Court case dealing with a constitutional attack on K-12 sex-segregated schooling, Vorchheimer v. School District of Philadelphia, 430 U.S. 703 (1977), the justices affirmed the court of appeals’ rejection of the challenge by an equally divided vote, leaving no precedential trail.