"Starting on April 11, US citizens will be able to select an X as their gender marker on their US passport application, and the option will become available for other forms of documentation next year," Blinken said in a statement.
Blinken said the policy was in keeping with the State Department's aim of providing inclusive service to all citizens, "regardless of their gender identity."
The State Department had previously announced last June that it was working to allow citizens to select a gender other than male or female when applying for passports, but did not indicate when the change would go into effect.