The department issued the guidance after widespread confusion over whether passports with “X” sex markers would be valid for international travel.
ABC News has reached out to the State Department for comment on the lawsuit.
Her mother worries that Mellow might not be granted a passport — or that it could create legal problems if her documents don't match or because she swore to something that's not true.
Secretary of State Marco Rubio, in a memo reviewed by NBC News, said additional guidance would be issued on existing passports containing an “X” sex marker.