"We look forward to offering this option to all routine passport applicants once we complete the required system and form updates in early 2022", department spokesman Ned Price said in a press release.
In addition to passports, the X marker will also be available on all Consular Reports of Birth Abroad (CRBAs), a move that presumably would allow parents to choose a gender-neutral designation for newborns, the official added.
The policy change is intended "to better serve all US citizens, regardless of their gender identity", according to Price.
"I want to reiterate, on the occasion of this passport issuance, the Department of State’s commitment to promoting the freedom, dignity, and equality of all people – including LGBTQI+ persons".
The marker would be applied to non-binary, intersex, and gender non-conforming persons applying for a US passport or CRBA, according to the release.