The Trump administration has issued a new rule for airlines requiring an end to gender demarcations besides male or female.

U.S. Customs and Border Patrol issued a new rule, citing an executive order signed by President Donald Trump the first day of his new term. The regulation demands carriers to update guidance for their Advance Passenger Information System, or APIS. Under Democratic President Joe Biden, airlines could note passenger gender with as male, female or other, but can no longer afford that recognition to genders outside the binary.

“Existing APIS regulatory language provides that ‘M’ or ‘F’ (M=Male; F=Female) sex markers are to be accepted in the transmission. However, CBP systems had previously accepted characters other than ‘M’ or ‘F’ without returning an error response or requiring resubmission,” the new rule states.

“Effective July 14, 2025, air carriers will have an informed compliance period of 90-days where values other than ‘M’ or ‘F’ in the sex field will not require resubmission. After the compliance period, APIS will begin returning a resubmit or ‘X response’ which indicates insufficient information requiring resubmission, when values other than ‘M’ or ‘F’ are submitted in the sex field.”

That means as of October 12, airlines will no longer be able to submit an alternative gender. The change also makes clear if airlines submit a male or female designation that is different than anything submitted on the original travel document, the carrier won’t face any type of penalties.

Airlines who face questions must call up CBP offices in Honolulu, Miami or New York, depending on the region.

Of note, the ACLU challenged Trump’s order in February, and a judge in June issued an injunction requiring the State Department to issue passports and other travel documents with alternative gender markers. The State Department is continuing to fight in court for the right to revoke or replace those documents and require male or female designations on every form.

But CBP is part of the Department of Homeland Security, and has authority over any international flights to and from the United States.

A CBP spokesperson acknowledged to The Guardian that the gender marker on any traveler’s documents “is not criteria for an applicant’s admission into the U.S.”