TRANSGENDER: is s/he genuine?

heh, long story, but i would sincerely appreciate your opinion on this, yes?

i have a friend. born female, who for most of her early teenage life was comfortable identifying as such. recently, she has become interested in 'Yaoi' or homo-erotic fantasies between men, and as far as i can remember she has always been interested in cosplay, or other roleplaying games. a few months ago, she decided she was bi-sexual and found a girlfriend who also enjoyed yaoi and roleplay. but, in the last two weeks, my female friend has began requesting we refer to her as 'him'. s/he got his/her haircut short, has taken to binding his/her breasts, and wears male clothing. naturally, as his/her friend, i try my hardest to offer support, but i cant help but feel a little... uncomfortable with this sudden inexplicable change. emotionally, they act very much the same as always. that is, he/she retains many of the emotional tendencies of a female, and so i often make the mistake of mis-adressing, refering by defult and entirely by accident to said person as 'she'. at first i worried about it, but then i began to realize hey, s/he doesn't even seem to notice. on top of that, i have noted that on numerous occasions s/he has accidentally referred to him/herself as female without being aware of it, and i must admit i interpreted this as a signal that something was not quite right with this situation.

i have a loose theory, that is that s/he has taken on this new male identity as a roleplay in much the same way s/he would assume a cosplay character, in order to share the homo-erotic fantasies with his/her partner. after all, the likely hood of finding a MALE partner willing to accept that their girlfriend enjoys yaoi is low. of course, this theory may be entirely wrong, s/he may be being quite genuine about the whole thing, i just... it sounds horrible but i truely feel that there is something fishy about the whole thing.

im not uncomfortable with him/her being transgender in the least, but i am uncomfortable with the thought that perhaps it is all an act, and that by acting in this manner s/he is being disrespectful and immature.

what do you guys think? am i reading to far into this? do you believe s/he is genuine and im just being a jerk?

maybe i am just being a jerk. :/