A conservative activist group in Maryland has launched a petition that calls for a referendum on the newly approved Fairness for All Marylanders Act of 2014, which expands protections for transgender individuals.

Leaders of the group, MDPetitions.com, said at a news conference Tuesday that their chief concern with the legislation is that it will allow a person who was born male to use women’s restrooms if that person identifies as female. The activists worry this will enable sexual predators to assault women and girls, and have dubbed the legislation the “Bathroom Bill.”

“It opens it up to predators, not necessarily transsexuals, but predators who will take advantage and go into the opposite-sex bathroom,” said Del. Neil C. Parrott (R-Washington County), who is chairman of the group.

Under the Maryland constitution, recently passed laws can be petitioned to the ballot by gathering signatures from the equivalent of 3 percent of those who voted in the last race for governor, which this year is around 55,700.

Proponents of the Fairness for All Marylanders Act say they consider the law an important piece of civil rights legislation that will ban discrimination based on gender identity in employment, housing and public places, which includes hotels, restaurants, theaters and sports venues. It includes an exemption for religious organizations, private clubs and educational institutions.

Restrooms were included in the legislation because lawmakers said transgender people are often ridiculed and sometimes assaulted when they use restrooms assigned to the genders of their birth. Supporters of the bill argued that there is no evidence that this law will be used by sexual predators to commit crimes, and criticized opponents for their insensitivity.

“Delegate Parrott’s misleading comments about bathrooms would almost be comical if he weren’t using these scare tactics to confuse the public and oppose basic civil rights protections in employment, housing, services, and public spaces,” Jer Welter of the FreeState Legal Project, a legal advocacy group that assists Maryland’s low-income lesbian, gay, bisexual and transgender community, said in a statement on Tuesday.

Gov. Martin O’Malley (D) has praised the legislation, which was in the works for more than seven years, and has said he plans to sign it into law.

MDPetitions.com pioneered the use of Web-based technology to collect signatures for petitions and has played the lead role in challenging newly passed laws by putting them on the ballot, including the extension of in-state tuition rates to undocumented immigrants, same-sex marriage and a congressional redistricting plan. All three measures were upheld by Maryland voters. The group also tried gathering signatures to put the repeal of the death penalty to a vote, but failed.

Parrott said the group aims to gather 25,000 signatures to support a referendum on the transgender law by the end of May and then 50,000 more by the end of June.

The news conference was held in the hallway outside the Maryland State Board of Elections in Annapolis. The group debated herding reporters into a restroom to do interviews, but deemed the lighting not suitable. Instead, activists stood in front of a banner that showed a stick-figure man climbing over the wall of a stall to look at a stick-figure woman.

“The unintended consequences of this law demand that we take it to a petition,” said Del. Kathy Szeliga (R-Baltimore County), who said that she is worried about the safety of girls and women. “The legislature rushed this bill through, hastily, and would not accept any good amendments to make this bill better, so it is time to take it to referendum and make the legislature come back and do this right.”

John Wagner contributed to this report.