I sincerely apologise for the forthcoming ramble. I'm a little late coming to this thread, so feel free to ignore what follows. But these are a few of my thoughts.
Looks like a lot of people are more obsessed with creating labels than actually asking why they need to, or why these labels have to apply. You act in a certain way, let's invent a condition for it. I read through those links Sarah B posted and a couple of things struck me.
It seems that some people only pursue a hypothesis until such a time as it produces results sufficient to validate their theory. After that, they stop looking. Quite
why these results are what they are seems to have been utterly disregarded in favour of being able to say "I'm right." If you ask someone why they feel the way they do, and they don't know, that doesn't give you the right to go ahead and just make up a reason and
tell them that's what it is.
Everyone knows on some level why they do what they do or feel how they feel, that doesn't mean they
know that they know. And in this case, it seems like no effort has been made to find out the deeper issues. This whole ->-bleeped-<- thing is just very superficial, very 'surface level'. It attempts to categorise the 'what' with no thought as to the 'why'. And that, in my opinion, is about as useful as trying to explain why light comes from the sun by saying "because it's a star", with no attempt made to understand nuclear fission.
Speaking personally, after 13 years of facing sexual situations as a 'male' and being utterly repulsed by the thought of doing it as a man, with everything being just wrong and like looking through the wrong side of a mirror, then doing it because it's what the other person wants, and seeing her pleasure in what you're doing and the way
her body is aroused while at the same time wishing you could trade places and fighting the urge to go take a shower and scrub your skin off... the idea of doing it the
right way definitely illicits a reaction in me (as long as I'm attracted to the person I'm doing it with - it can't just be Josephine Public here). I'm sure as heck not going to deny myself the ability to use my imagination in a perfectly natural way that everyone on earth does at one time or another just because some fusty know-it-alls have to slap a tag on it.
The only thing which even slightly worries me about picturing such situations, is whether my partner is going to keep me awake all night with the snoring afterwards.

Sexuality and gender... well, I don't honestly care what the two do or don't have in common. It's not something I lose sleep over. What I
do care about, however, is that I see sexuality as part of living a normal life, and
that does matter to me. And while I may not ever have the original plumbing to go with the electrical wiring... hey, a girl can dream.
All I would say to you, is go with your instincts. They stem from a far deeper place than anyone's opinion can ever reach. Don't be scared to feel because you're afraid that someone will tell you what you're feeling is wrong.
Ramble over. Normal programming may now resume