Mary Marvel predates the introduction of a character created by Otto Binder and she is significant.
Mary Marvel . Created by Otto Binder and Marc Swayze , she first appeared in Captain Marvel Adventures # 18 ( cover-dated Dec. 1942 ) . Mary Marvel was one of the first female spin-offs of a major male superhero , and predates the introduction of Superman 's female cousin Supergirl ( also created by Otto Binder ) by more than a decade .