Alright. So I going to fill out the application for my new social security card, with my new name on it. Do I check male or female? I wanna check female so bad. I was thinking about checking female, and having my endo write a letter stating I am under clinically apporitate treatment.

You should probably check "male" unless you have an acceptable letter (some folks have had success with letters that say nothing about surgery).  Or you can leave it blank and see what they do. Do you have other identification, such as a driver's license? If so, what do they say?

I have a female driver's license.

Well, since you are currently listed as male, the clerk will have to make a conscious decision to change that to female. So you probably have to point out that you want your sex marker changed. I think. I can't remember what kinds of forms they use...do they have one for sex marker changes yet?

I was thinking that you could leave the box blank or fill in "F' and just see what happens, but I think you'll have to specifically request that the sex marker be changed. If that's the case, you might hold the letter back until you are asked to provide proof.

And see if you can get some kind of printout right then and there that shows the changes. Otherwise, you'll have to pay for it later if you want verification.