Therapists in Massachusetts can no longer practice so-called conversion therapy on minors, thanks to a new bill signed into law by the state’s Republican governor.

Gov. Charlie Baker signed legislation on Monday that prohibits licensed health care professionals from providing conversion therapy to patients under 18.

“Governor Baker today signed HR140 into law and is proud of the Commonwealth’s history of support for equal rights and protecting all citizens against discrimination,” Brendan Moss, a spokesman for the governor, told HuffPost on Monday.

With the new law, Massachusetts joins 15 other states and Washington, D.C., in banning the dangerous and discredited practice that attempts to change a person’s sexual orientation or gender identity. Colorado will likely follow suit, with lawmakers there sending a bill to Gov. Jared Polis (D-Colo.) last Friday for signing.

Per The Associated Press, conversion therapy can involve interventions ranging from talk to electric shock. In a 2009 report, the American Psychological Association found no evidence that performing conversion therapy on minors alters their sexual orientation. APA researchers condemned the practice, writing that it approaches “homosexuality as a mental disorder, a concept that has been rejected by the mental health professions for more than 35 years.” They found that negative side effects of conversion therapy can include depression, suicidality and anxiety.

“We’re saying that this dangerous, abusive behavior will not be tolerated,” said Massachusetts state Sen. Mark Montigny (D), who sponsored the state Senate version of the bill, after its passage in March.

The ban does not extend to the practices of religious leaders, nor does it address conversion therapy performed on adults.

According to The Republican, a Massachusetts-based newspaper, Baker signed the bill over objections from Republicans in the state Senate who felt the ban would infringe upon therapists’ free speech rights, as well as the right of parents to make decisions for their children.