Consistent with constitutional principles, a school board may establish a single-sex school or class in the school division, if the school board makes available to pupils substantially equal coeducational schools or classes. Participation in such single-sex school or class shall not be required by the school division, and the school board shall ensure that participation by pupils in the single-sex school or class is voluntary. For the purposes of this section, participation by a pupil in a single-sex school or class is voluntary only if the school division also makes available to the pupil a substantially equal coeducational school or class.