The U.S. Customs and Border Protection (CBP) is now requiring airlines to assign either “M” or “F” to all passengers in its Advance Passenger Information System, even if a traveler’s passport uses an “X” gender marker. The change takes effect after a 90-day compliance window ended as of October 12, 2025, meaning that submissions of any nonbinary marker will now be result in an error and need to be altered. This essentially means that airlines must instead guess and submit “M” or “F” without penalty. Although U.S. passports with “X” markers remain technically valid, the policy may force discord between what’s on a traveler’s documentation and what is entered into CBP’s systems. This policy will also affect people from other countries coming into the U.S. with X gender markers. Canada, which has offered an X gender marker since 2017, recently joined other countries in issuing a travel advisory for trans passengers traveling to the United States, suggesting that the United States may t...