Thousands of demonstrators on Friday gathered in downtown Sao Paulo to protest a recent ruling that overturns an 18-year ban on therapies that attempt to alter the sexual orientation of lesbian, gay and bisexual people.

According to the Los Angeles Times, the protesters waved rainbow flags and chanted “it's not a disease” over songs including Lady Gaga's Born This Way.

One of the protesters, Carlos Daniel, said that the decision threatens the lives of LGBT people.

“We have to help people understand that this decision wasn't something small,” he said. “These types of thoughts are what get us killed here in Brazil every day. We are dehumanized and treated like objects. We have to show everyone that we exist and that the future is ours.”

The decision involves an evangelical Christian and psychologist whose license was revoked in 2016 for offering “conversion” therapy in defiance of a 1999 decision by the Federal Council of Psychology that banned such treatments.

Waldemar de Carvalho, a federal judge in the capital of Brasilia, sided with Rozangela Justino, who has said that she views homosexuality as a “disease.” Carvalho has since said in a statement that he does not believe homosexuality is a disease.

The Federal Council of Psychology criticized the ruling in a statement, saying that it “opens the dangerous possibility of the use of sexual reversion therapies.” The group said it would appeal the decision.

“There is no way to cure what is not a disease,” Council president Rogerio Giannini told the Guardian. “It is not a serious, academic debate. It is a debate connected to religious or conservative positions.”

Evangelical Christian groups opposed to LGBT rights have seen steady political gains in Brazil and routinely protest television shows that feature gay or transgender characters.