Just What Is A Mary Sue?

I know you guys can answer this question for me. I know that the term came into existence to describe idealized (mostly) heroines in Star Trek fanfic, but it seems to have mutated and evolved over the years to encompass a wide variety of characters, both male and female (and in SF and fantasy, presumably non- and… » 3/24/13 2:24am 3/24/13 2:24am