Image copyright Getty Images Image caption Bathrooms in the US have become a political battleground

Online business review site Yelp is introducing a new feature to help US customers find gender-neutral bathrooms.

The website announced it will add the function in a blog on Friday.

It classes a gender-neutral bathroom as a locking, single-stall toilet accessible to people of any gender.

It comes a day after Yelp announced its support for transgender teen Gavin Grimm in his Supreme Court battle against his local school board.

Yelp was one of 53 companies - including AirBnB, Apple and Microsoft - which signed a friend-of-the-court brief, filed on Thursday.

Gavin, 17, is arguing that the school board in Gloucester County, Virginia, has discriminated against him and that its bathroom policy - which means he cannot use the boys' toilets because he was born a girl - violated his civil rights.

Bathrooms in the US have become a political battleground in recent years.

Last month, Donald Trump's new administration revoked guidance to US public schools that allowed transgender students to use toilets matching their gender identity.

Image copyright Yelp Image caption Yelp bustomers or businesses are able to input the information

In its blog, Yelp said it was "important for the business community to speak up in support of equality for all".

"At Yelp we thrive on inclusion and acceptance," Yelp said.

The idea for the new feature, which began to be rolled out on Friday, came from Yelp employees.

Customers or business owners can update the site's information and eventually people will be able to search the website for businesses with gender-neutral bathrooms.

"The hope is that this feature gets business owners thinking about how they're presenting themselves - who they're supporting and why," said Rachel Williams, Yelp's head of diversity.