Source: U.S. Department of State: Selecting your Gender Marker

As of 2022 April 11^th (next week, Monday), it will be possible to apply for a United States of America passport with an "X" gender marker indicating "unspecified or another gender identity" [other than male (M) or female (F)]. Gender for passports is self-reported and does not require any documentation, medical or otherwise. The gender listed on one's passport application does not need to match the gender listed on one's other identity documents or citizenship evidence.

Issues

Gender should not have legal significance. People should not be classified differently on legal documents based on their gender, just as race, class, sexuality, religion, etc. should not be fields on government-issued identity documents. My official stance is that rather than adding more gender options, the gender/sex field should be removed from the document entirely.

(It should also be noted that gender for some people may be fluid or otherwise complicated in ways that just adding more options may not adequately address.)

Furthermore, I'm concerned about the implications of creating a list of nonbinary citizens (a group that might be targeted by a more conservative administration in the future).

This is good, though!

Those issues aside, I do think this is a good thing! It is especially good (and refreshing!) that gender can be self-reported.

I am a gender-nonbinary USA citizen in need of a passport. I will apply for a passport with an "X" gender marker soon.

(Update: I now have my passport, and it lists "Sex/Sexe/Sexo: X".)