It's been a long time since I watched Otoboku, but I've always wondered if the visual novel explained what happens to Mizuho after he graduates and puts aside his façade.
Mizuho is a guy disguised as a girl, attending an all-girls school. He doesn't exactly keep a low profile, either; if he'd done that, he could have just made his girl form disappear after graduation and gone back to being a man. Instead he runs for Elder and becomes a celebrity who is looked up to by the younger girls. When he graduates, he can't just throw off his wig and dress, go "Phew, what a relief", and be a man again, because tons of his former classmates recognize him. He would have to either tell them all "Yeah, I was crossdressing all those years and hanging out in the dressing room and bathrooms with you" and get arrested for a pervert, or else pretend to be his own brother (or something) and get out the disguise again whenever his old school friends come around.
Yes, seriously, that's a guy.
If I remember correctly, Mariya, Takako, and Shion all know by the end of the anime series that Mizuho is a guy. Yukari and Kana never find out. So at some point he's going to have to break it to Yukari and Kana, even if he decides to never see anyone else from the school again. (According to the Wikipedia article, though, he, Shion, and Takako often visit their old school after graduation.)
The Wikipedia article says the VN does show what Mizuho does after he graduates. Does it address this? Does he maintain his female disguise or eventually break it to everyone that he was a guy the whole time?