SAN FRANCISCO – A U.S. appeals court on Thursday upheld the country’s first-of-its-kind law banning health practitioners from offering psychotherapy aimed at making gay youth straight.

Supporters of the ban say the methods therapists use to try to change youngsters’ sexual orientations are unethical and ineffective and can put them at increased risk of suicide.

The 9th U.S. Circuit Court of Appeals ruled that California’s ban on so-called conversion therapy for minors doesn’t violate the free speech rights of licensed counsellors and patients.

Supporters of the ban, including Gov. Jerry Brown, say the therapy’s efficacy has been questioned or rejected by every major mental health professional association.

New Jersey’s governor has signed a similar law that would ban conversion therapy in his state. California and New Jersey are two of the most populous states in the country.

The case was brought by professionals who practice sexual-orientation change therapy, two families who say their teenage sons benefited from it and a national association of Christian mental health counsellors. They argued the ban infringes on their free speech and freedom of association and religious rights. The counsellors also argue it jeopardizes their careers.

But the court held that California has the power to prohibit licensed mental health providers from administering therapies deemed harmful.

The activities of pastors and lay counsellors who are unlicensed but provide such therapy through church programs would not be covered under the law.