Look deeply and you will see that the Torah does not know of man and woman as separate beings. Each act is performed once through a single body-a body that in our world may appear as two, but which the Torah sees as one.
On the contrary, for both to do the same mitzvah would be redundant, for why should one half of the body do what the other has already done?
They are a single whole, whether they know of one another or not. Where does a woman put on tefillin or wear tzitzit? On the body of her male counterpart.
