Wait, how and why do they give this person an involuntary sexual reassignment surgery? Discarding the why for now, since I'm sure they'll have some contrived reason, how exactly do they do this? Forgive my ignorance on the specifics of such procedures, but don't they often involve years of hormone treatments? I mean, you could give a person surgery, but without the long duration aspects they'll still just look like a guy, except for down stairs. What's more, their voice would still be the same. In such a case, would it not be more accurate to cast a man to play this character, rather than a woman, since this character couldn't possibly look like more like a woman than a man after only the surgery itself? Unless this character is actually going to be kidnapped and given years of hormone treatment, or maybe some kind of sci-fi medical procedure.
I'm not expecting absolute accuracy, but if you're going to make inaccurate elements then you ought to do them in a way that's not immediately obvious. Considering I know virtually nothing about such procedures, yet have immediately noticed the errors, I'm not sure how I could possibly suspend my disbelief at all this.
Oh, and I have no interest in this movie, so if they think I'll watch it to find out, they're wrong. I'm sure I'll forget about it until it's released and people inevitably begin talking about it again.