Transgender

My guess is put the information they identify with while they are alive, to keep the privacy of their "medical" condition.

However, when they are deceased, you can put their birth name in, put their legal name at death in, checkmark the box for the gender they identified with because that might also be the legal gender, but in the bio, describe the transition.

I think arguments can be made for each of the three choices for Gender
At Birth -- at death -- and unknown since neither was it for whole life

Private User I agree.