Mich. Comp. Laws § 380.475: Single-gender school, class, or program; establishment; availability of equal coeducational school, class, or program.

Sec. 475.

(1) Subject to subsection (2), the board of a first class school district may establish and maintain a school, class, or program within a school in which enrollment is limited to pupils of a single gender if the school district also makes available to pupils a substantially equal coeducational school, class, or program and a substantially equal school, class, or program for pupils of the other gender.

(2) If the board of a first class school district establishes a single-gender school, class, or program described in subsection (1), the school district shall not require participation by any of its pupils in the single-gender school, class, or program. The board shall ensure that participation by pupils in a single-gender school, class, or program is wholly voluntary. For the purposes of this subsection, participation by a pupil in a single-gender school, class, or program is not considered to be voluntary unless the school district also makes available to the pupil a substantially equal coeducational school, class, or program.