New York City Mayor Bill de Blasio has signed an executive order that allows transgenders to use city-owned facilities that correspond to their gender identity.

The order requires city agencies to allow employees and the public to use city single-sex facilities without being required to show ID, medical documentation or any proof or verification of gender.

It covers city-owned buildings including city agency offices, public parks, pools, playgrounds, certain museums and recreation centres for the NYC's estimated 25,000 transgenders and gender non-conforming individuals.

"Every New Yorker should feel safe and welcome in our city – and this starts with our city buildings. Access to bathrooms and other single-sex facilities is a fundamental human right that should not be restricted or denied to anyone," he said in a statement.

The order, he said, "makes it clear that New York City fully supports the right of every New Yorker to use the single-sex facility consistent with their gender identity."

The executive order follows a recent legal enforcement guidance issued by the NYC Commission on Human Rights that says any employer, housing provider or public accommodation that denies access to bathroom or single sex facilities based on gender identity can be prosecuted for violating the NYC Human Rights Law.

Gender identity has been a protected class under the law since 2002, when it was added to the NYC Human Rights Law following an amendment sponsored by then Council Member Bill de Blasio.

De Blasio's order requires city agencies to post the single-sex facility policy in conspicuous locations within three months and make an update that they have already complied with the new rule.

City agencies may seek exemption from certain provisions of the executive order by sending a request to the Commission on Human Rights.

Bathroom bills are being debated across the U.S. as parents and elected officials express their opposition because of privacy and security concerns, including men using the rule to access bathrooms to attack women.

De Blasio's press statement noted that Missouri, Tennessee, Virginia, Oklahoma and Washington are considering or have pending bills to prevent transgenders from using bathrooms that conform to their gender identity.

South Dakota Republican Gov. Dennis Daugaard recently vetoed a bill that would have prevented transgender students from using bathrooms that correlate to their gender identity.

However, former transgender Walt Heyer, 75, said, "Nobody's ever born a transgender. They're manufactured as a result of something, a developmental childhood issue that has yet to be determined for many people," according to the Daily Mail and Christian News Network.

Heyer underwent sex change operation in the 1980s to become a woman before going back to being a man. He said Christ redeemed his life.

"God designed man; He designed women. God will redeem the lives of people who struggle with gender identity issues just like I did. He redeemed my life, and I've been free from it as a result of that," he said.