Rumiko Takahashi, the creator of the martial-arts comedy manga Ranma 1/2, in which the character Ranma is cursed with the body of a woman whenever he is doused with cold water, is herself a woman.As the OP points out, it's incredibly, incredibly rare.It was bad but it was what you were looking for, kind of. Apparently El Goonish Shive handles a variety of gender swaps but I'm not following that either. That's what I can gather from a skim of the gender swap page, anyway... nah, twenty times at least the other way round.males...(Apparently it was Hot Chick) As for actual "girl transforms into boy" stories... Vision of Escaflowne kind of treats it but it's far from centered on, it just... CUTEx GUY apparently focuses on it, but I'm not familiar with that work. ( Something Special seems to center on it, but again, never encountered it. Well, from a feminist perspective, for a great deal of human history it's been easier to be male than female in most ways - especially the ways that "matter".Combine the three, and you have this: a man turning into a woman has drama, excitement and comedic fuel. A man becoming a woman is going from the standard to the non-standard. Dating the Enemy does a bit, but it's kinda hard to say seeing as neither of the main characters are really paragons of masculine and feminine stereotypes to start with (e.g. I dont have any examples, like you said, it seems really rare.the woman is a slob, the man constantly preens over his appearance; he (as her) has to deal with periods and PMS, she (as him) has to deal with... But at least I HAVE read stories of male to female (permanent) where it isnt treated as a comedy. Naruto gets turned female and spends probably the first half of the story trying to avoid a full on mental breakdown over his/her loss of identity.
She had something pretty close to a breakdown at the end of it due to psychological stress (which might be one of the reasons this trope is rare) in her case she found that being male wasn't "easy" at all.
Thus, in fiction, a man becoming a woman is a curse, but a woman becoming (or pretending to be) a man is something she chooses in order to better her own position or to achieve some goal that being a woman prevented her from achieving (Ex: the movie Mulan, where the title character pretended to be a man so she could join the army in ancient China).
I should point out that this "truth" of drama isn't just held up by male authors.
There are quite a few modern stories (webcomics, manga, etc) about how a guy magically/scientifically gets transformed into a girl (or woman), and there are also a fair number of stories (some classical, some modern) where a female dresses up and pretends to be a guy or takes on a usually-masculine role.
But there seem to be very few stories where a girl gets transformed into a male character, and doesn't want to be.