I used to think Poison had the Sex Change up until a few Months ago when TiamatRoar said more or less what he posted above. Poison’s a man. There is also the example that was given on how Poison sounds a lot more feminine in SF3 then she does in Final Fight indicating that Poison had the Sex Change.
But, as what has been revealed to me in a discussion on another forum where this came up, is that Poison having a Sex Change would not make her sound more feminine unless she had said Sex Change during Puberty. Most Trans sound more Feminine over time due to practicing there voice to sound more feminine.
The Comic has done nothing to indicate Zangief is Gay, so they probably won’t do anything to indicate that Poison’s a man.
Course, nothing in the Comic contradicts Zangief being Gay either.