In regards to Poison's gender, here is a note from Street Fighter X Tekken producer Yoshinori Ono:
"Capcom's official stance has and will continue to be that we don't have a stance technically. It's supposed to be mysterious; if people want to talk about it on forums or what not they're welcome to, but we're not going to give you a straight answer because, well, there isn't one. We deliberately want to make it a mysterious thing-that question of what's at the core of this character. At the end of the day, we don't have an actual canonical answer to that.
It's interesting, because it almost takes on a sort of Rorschach test. If you go into it with the pre-conceived notion that she's a woman, the way she talks, the way she moves, you'll see all of that as being very feminine. If you go in with the pre-conceived notion that she's not, her actions and mannerisms will seem the other way to you. So, it's very open-ended.
From my point of view, I'm very happy to have fans continue to discuss that, but once again we're not going to give an official answer. We're happy to leave that open and up to individual fans."