The opinion back at that time was that the militia was comprised of ALL MEN able to bear arms. That is why the right was expressly given to the PEOPLE. I do not believe that women were yet considered to legally be people back then. That did not come until much later, as women eventually gained equal rights with men.
Jefferson was the main person behind having a Bill of Rights added to the Constitution. In fact, he insisted on it, in order to gain his support for the Constitution. He viewed it as being protection for the people from losing key rights to either the Federal or State governments.
Here are quotes from Jefferson on these two issues:
"A bill of rights is what the people are entitled to against every government on earth, general or particular; and what no just government should refuse, or rest on inferences." --Thomas Jefferson to James Madison, 1787.
"The governor is constitutionally the commander of the militia of the State, that is to say, of every man in it able to bear arms." --Thomas Jefferson to A. L. C. Destutt de Tracy, 1811.
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