Maryland Governor Martin O'Malley on Thursday signed a law outlawing discrimination against transgender people.

“Signed the Fairness for All Marylanders Act today,” O'Malley tweeted to his nearly 52,000 followers.

He added in a second message: “In MD, we've passed marriage equality, outlawed discrimination against transgender MDers, and extended health benefits to same-sex couples.”

The Fairness for All Marylanders Act of 2014 (SB 212) prohibits discrimination in the areas of employment, housing, credit and public accommodations on the basis of gender identity or expression.

Senator Richard S. Madaleno, an openly gay Montgomery County Democrat who for eight years championed the bill in the Senate, was handed the pen O'Malley used to sign the transgender protection law.

“It provides important protections for people who are just trying to live their lives,” Madaleno said after the ceremony.

Last month, a group of Republican lawmakers opposed to the measure launched a ballot initiative to repeal the law. Opponents have dubbed the legislation the “Bathroom Bill” and its repeal campaign includes imagery of a stick-figure man climbing over a bathroom stall to reach a stick-figure woman.

Delegate Neil C. Parrott said repeal was needed because the law “opens it up to predators … who will take advantage and go into the opposite-sex bathroom.”

However, a last-minute amendment to the bill added to counter such claims defines gender identity as being “sincerely held as part of the person's core identity.”