Mississippi Code Title 33. Military Affairs § 33-5-1

The militia of the State of Mississippi shall consist of all able-bodied citizens of the state between the ages of seventeen (17) and sixty-two (62) years, who are not exempt by law of this state or of the United States, together with all other able-bodied persons who shall voluntarily enlist or accept commission, appointment or assignment to duty therein, subject to such classifications as may be hereinafter prescribed. The militia shall be divided into three (3) classes: The National Guard, the Mississippi State Guard, and the unorganized militia. The unorganized militia shall consist of all persons liable to service in the militia, but not members of the National Guard or the Mississippi State Guard.

A seventeen-year-old person shall not be allowed to enlist or be assigned to duty without the written consent of both parents, if living, or one (1) parent if one (1) is deceased, or if both parents are deceased, the guardian of such person.