The state of Oregon has approved a new rule giving its residents the option of not specifying their gender on driver's licenses.
Under the new rule approved by the Oregon Transportation Commission, Oregonians who select the new option will have an X appear instead of M for male or F for female on the cards.
LGBT rights groups praised the move while other states are looking to do the same.
In California, the state Senate by a 26-12 vote passed a bill on May 31 to add a third gender option on state IDs, sending it to the California State Assembly.
The California Family Council, a conservative Christian group, opposes it, arguing that "government documents need to reflect biological facts for identification."
"We believe government documents need to reflect biological facts for identification and medical purposes," said California Family Council CEO Jonathan Keller.
"Secondly, the bill advances a falsehood: that being male or female, or no gender at all is a choice each person must make, not a fact to celebrate and accept. Laws like this will simply erase any meaningful gender definitions, if being male or female is completely divorced from biological facts."
Meanwhile, India, Bangladesh, Australia, New Zealand and Nepal already recognize non-binary genders.
The Canadian province of Ontario implemented the X option earlier this year.
The rule goes into effect in Oregon on July 3.