10 USC 311: (a) The militia of the United States consists of all able-bodied males at least 17 years of age and, except as provided in section 313 of title 32,

10 USC 311: (a) The militia of the United States consists of all able-bodied males at least 17 years of age and, except as provided in section 313 of title 32, under 45 years of age who are, or who have made a declaration of intention to become, citizens of the United States and of female citizens of the United States who are members of the National Guard. (b) The classes of the militia are— (1) the organized militia, which consists of the National Guard and the Naval Militia; and (2) the unorganized militia, which consists of the members of the militia who are not members of the National Guard or the Naval Militia. The first half (the prefatory clause) needn't be ignored for the Second Amendment to apply to everyone - unless you're arguing for firearms restriction to apply only to women of all ages and men over age 45, but I doubt that's the case.