Normally, as a man, then I get treated as such. So if I present myself as Melanie, a woman, then...? Seems pretty self evident to me.
Now if a guy is dressed in womens clothes but not presenting themselves as such- in terms of their name, mannerisms, overall gender identity, then you would treat them as a man.
There is a difference between a man dressing as a woman vs a man identifying themselves and presenting as a woman.
Melanie