New York City will allow people who do not identify as male or female to change the gender designation on their birth certificates to X.

The legislation adopted on Wednesday will also allow transgender people to change the gender on their birth certificates without an affidavit from a doctor or mental health professional.

And it will allow parents to choose the non-binary X for their newborns’ birth certificates.

New York City stockThe Empire State building in New York (Ian West/PA)

City Council Speaker Corey Johnson, a Democrat, said the gender-designation bill is part of making New York a more inclusive city.

He said gender “is a spectrum for many people. It’s not a fixed thing”.

Some places in the US already allow such designations, but the nation’s largest city taking such a step is significant.

Democratic mayor Bill de Blasio is expected to sign the bill which would go into effect on January 1.