During a recent conversation about female superhero code names, it occurred to me that, for the first half-century of comic books, the titles "Captain" and "Doctor" were exclusively reserved for male characters, like Captain America or Doctor Fate. The first female characters I could think of to carry those titles were the Monica Rambeau version of Captain Marvel and the Kimiyo Hoshi version of Doctor Light over at DC. It struck me as interesting that the earliest women I could think of with these titles had borrowed them from pre-existing male counterparts.
So my question is, are Captain Marvel and Doctor Light in fact the first super-heroines to use those titles, or was there someone prior to them I'm forgetting? If these are indeed the first, does anyone know the first time "Captain" or "Doctor" were used for female characters who were NOT based on prior male versions?
To clarify: I'm specifically looking for a Code Name adopted by a female character (a la Captain Boomerang or Doctor Octopus), not just a character who is actually a Captain or Doctor.