In NY City at least it is going to be as simple as having a note from your doctor. Once you have that all important note, your birth certificate can be altered to identify you as the opposite sex. This is such a testimony to the confusion of our times. If you an one specialist think that you are a man instead of a woman or vice versa then it is so. What if I think I am a lion and one specialist agrees, can I change my birth record to read "lion."
Isn't it a bit more simple to just accept ourselves the way that God has made us?
Genesis 1:27 God created man in His own image, in the image of God He created him; male and female He created them.NASB95
Anything less is really just rebellion aginst the creator. Christians call that sin, but there is an answer to the problem: Christ.
Romans 5:8 But God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us.NASB95