Can one lose their identity if their appearance changes drastically?

Question

If a person altered their appearance suddenly and drastically, their sex, apparent ethnicity, eye color, height, all of these changed, would that person be in peril of having their identity (citizenship and credentials) contested?

If so, is there any evidence they could prepare in advance that would secure their identity? The person invented and would perform the procedure themselves, and their family may decide they're unrecognizable, so medical history and family testimony would not be helpful.

Answer 1

A US passport does not list height or make claims about ethnicity: what you have is a birth date and state, and photograph. A passport is taken to be strong proof of identity. You may apply for a new passport (turning in the old one), with a new photo. It may be necessary to provide "documentary evidence of identity" by appearing with an identifying witness (citizen or permanent resident) who has known you for 2 years and fills in an affidavit (both of you would need to bring some ID as well, so let's assume you also have a valid driver's license). It would be at the discretion of the accepting agent whether to believe that you and the "old" you are the same person. In the fictitious scenario, the person could videotape themselves undergoing the transformation, but ultimately, if one is sufficiently off the grid, then proving identity could be very difficult.

Answer 2

is there any evidence they could prepare in advance that would secure their identity?

Have a DNA test taken under circumstances when the identity of the person who is taking the test cannot be reasonably questioned (e.g. under forensic DNA lab protocols and with presentation of a passport with your pre-transformation photo).

If your identity is doubted after the fact, take a new DNA test to confirm that you are the same person. This was how the claim of a person to be Anastasia was ultimately resolved by the German courts. Her DNA was compared to an authenticated strand of the Russian princesses hair.

Finger prints and dental records are also often used to resolve such issues.