Mich. Comp. Laws § 37.2404a

Sec. 404a. (1) This article does not prohibit the board of a school district or intermediate school district or the board of directors of a public school academy from establishing and maintaining a single-gender school, class, or program within a school as provided under sections 475 and 1146 of the revised school code, 1976 PA 451, MCL 380.475 and 380.1146. (2) As used in this section, "school district", "intermediate school district", and "public school academy" mean those terms as defined in the revised school code, 1976 PA 451, MCL 380.1 to 380.1852.