New York City now offers a gender-neutral option on birth certificates for residents who don't identify as male or female. It's called "X."

As of this week, adults over 18 can alter their birth certificates to "X" so long as they attest via a form that the change "is to reflect my true gender identity." New York Mayor Bill de Blasio signed the move into law Tuesday, ABC reported.

"To all trans and nonbinary New Yorkers: We see you, hear you and respect you," the mayor said last week on Twitter. "Starting in 2019, all New Yorkers will be able to change their gender on their birth certificate to M, F or X – without a doctor's note."

Before 2014, New York City let people alter their gender on a birth certificate only after gender reassignment surgery. After that, a doctor's note was required.

Now parents can choose "X" for their children, and adults can select the marker for themselves as long as they attest the change is "not for any fraudulent purpose," the form states.

New York City joins states California, Oregon and Washington as places offering a gender-neutral option on birth certificates. New Jersey will follow suit in February.

Attorney Ethan Rice of Lambda Legal, an LGBTQ rights group, told ABC that New York City's gender-neutral category remains unavailable statewide: A person may choose X on a birth certificate but not a state driver’s license.

Oxiris Barbot, New York City's health commissioner, praised the move as "a less burdensome" option for the city's transgender and nonbinary residents, according to Newsweek, and Melissa Sklarz, a Queens-based trans rights activist, called the move a key "next step."

"It is important that young people be empowered to explore their identities in a manner that is relevant to them," Sklarz said, according to the magazine.

Contributing: The Associated Press

Follow Josh Hafner on Twitter: @joshhafner

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