Big-Cat
Challenge accepted.
It's a bit more complicated than that. In Japan, she's pre-op, but in America, she's post-op. Interestingly enough, Poison (along with Hugo) are never referred to with pronouns. Hugo likely got the same treatment so as to not look too suspicious as to why Poison was never referred to a he OR she.His in Japan, her in America.
However, because Poison is ultimately transgendered, with or without operation, it is out of respect to refer to a transgender person by their desired gender, a she in this case.