I'm going to guess not, at least not in the spirit in which you ask the question. I've never thought about there being elves who are ambiguous in or confused about their nature. But perhaps it is because their nature is easily knowable? Thus you wouldn't end up with a situation like "I was born with male genitalia but I feel like a woman in here"... it would be as if everyone could detect that you were a woman in there, so they would treat you as a woman without any fuss. That is, the outside (i.e. what people can detect) matches the inside (i.e. what you feel). So no ambiguity. In real life, wouldn't that be grand!

It does bring us back to the question of what *IS* nature, and how is it expressed? It obviously has a physical component since elves with incompatible natures are (so far as we know... Cat and Paul gave us evidence of this with their dew baby) apparently unable to reproduce.

But it is something programmed in your genes? Or is it something that you literally inherit from your parents, not as genetic code, but as some kind of transfer of magical essence that happens at conception?

I should mention that there is a concept of dual nature. There are a very small number of words which have an Air/Earth nature. The only three I have right now are the words for "ash tree", "family", and "all". Two of them are artificial concepts, but the ash tree is a living entity whose nature can be examined, so there must be something to it. Perhaps it is possible for an elf to have that dual nature. But that would be quite the sensation if it ever happened. If such an elf is ever born, his name will be Sinlir.