Mental health care practitioners in Oregon can no longer try to “convert” LGBTQ youth to heterosexuality, under a law passed last week by the state legislature.

HB 2307, passed by the Democrat-controlled state senate on Friday, will make Oregon the fourth jurisdiction, following California, New Jersey, and Washington, D.C., to ban so-called conversion therapy for minors.

The practice, in which mental health professionals seek to change a person’s sexual identity or orientation, relies on both the outdated belief that non-straight sexual orientation is a mental health disorder and the discriminatory belief that same-sex orientation is of less value than heterosexuality. The American Psychiatric Association (APA) removed “homosexuality” from the Diagnostic and Statistical Manual of Mental Mental Disorders (DSM) in 1973.

Conversion therapy, also called reparative therapy, has been lambasted by the medical and mental health professional communities, including the American Academy of Pediatrics, the American Psychological Association and the American Psychiatric Association.

There’s no evidence to suggest that conversion therapy works, according to a 2009 report by the American Psychological Association, which surveyed literature on the subject.

Banning conversion therapy has gained widespread support around the United States. Backed by the National Center for Lesbian Rights (NCLR), bills like HB 2307 have been introduced in 17 states across the country, most of them this year.

Both the California and New Jersey laws have recently held up in court. And in April, the Obama administration threw its support behind the bans, and in particular a push to enact Leelah’s Law, which honors Leelah Alcorn, a 17-year-old transgender woman who committed suicide last year, and which would ban all forms of conversion therapy.

Though bills like the one passed in Oregon are significant, they are also limited. As Christen McCurdy wrote for Rewire in March, these laws don’t “address all the ways in which conversion therapy is actually practiced—which can include ‘treatment’ for dependent patients over the age of 18, or from members of the clergy or other non-licensed individuals.”

Still, the Oregon bill is a significant step towards stopping the practice of conversion therapy.

“This lifesaving law will protect the health and well-being of LGBT youth in Oregon and ensure that licensed mental health professionals cannot abuse their position of trust to do lifelong harm to children and tear families apart,” NCLR campaign coordination and staff attorney Samantha Ames said in a statement.