NEW YORK — It's now law in New York City that residents who don't identify as male or female can change their birth certificates to "X."

New York City Mayor Bill de Blasio signed the bill Tuesday. It goes into effect Jan. 1.

The bill removes the requirement that residents need an affidavit from a doctor or mental health professional to change the gender on their birth certificates.

It also allows parents to choose the "X'' designation for their newborns.

New York City joins California, Oregon, Washington state and New Jersey in allowing a third gender option on birth certificates. Washington, D.C. allows gender-neutral driver licenses.

De Blasio, a Democrat, says New Yorkers should be free to tell their government who they are — and "not the other way around."