The justices on Monday let stand an appeals court ruling that said the state’s ban on so-called conversion therapy for minors doesn’t violate the free speech rights of licensed counselors and patients seeking treatment.

The 9th U.S. Circuit Court of Appeals ruled last year that California lawmakers properly showed that efforts to change sexual orientation were outside the scientific mainstream and have been rejected for good reason.

Liberty Counsel, a Christian legal aid group, had challenged the law along with other supporters of the therapy. They argue that lawmakers have no scientific proof the therapy does harm.