Here is my understanding from reading up on it. I am MTF and when I complete SRS, I will still have to keep registered for the draft. The current military looks at your original birth gender. So if you were originally born male, then you will have to keep registered, but you will be excused if they ever called you up, since you would have gone through SRS. Now if you were a female, it is my understanding you are still exempt due to your original gender. This is one reason I will keep my original birth certificate and social security card in a safety deposit box, you never know what you might have to prove in the future.
Now currently I don't see there being a draft. The current DoD leadership does not want one, they know they would not get quality soliders like they need through a draft. We learned this in Vietnam.