to require any student to certify that such student is not a member of a single-sex social organization or to disclose the student’s membership in a single-sex social organization. (2) Single-sex social organization The term single-sex social organization means a social fraternity or sorority described in section 501(c) of the Internal Revenue Code of 1986 which is exempt from taxation under section 501(a) of such Code, or an organization that has been historically single-sex, the active membership of which consists primarily of students or alumni of an institution of higher education. .