The U.S. Supreme Court refused Monday to review a challenge to a 2012 California law banning "conversion" or "reparative" therapy on minors — a practice that aims to turn gay people straight.

The justices, without comment, let stand a ruling by the 9th Circuit Court of Appeals from last August that upheld the law — the first of its kind — which prohibits licensed counselors and therapists from engaging such efforts to change the sexual orientation or gender identity of patients under 18.

Supporters of the law who fought to protect it in court such as Equality California and the National Center for Lesbian Rights (NCLR) said the high court's decision now clears the way for enforcing the ban in the state.

"This important legislation will permanently improve the health and well-being of California's most vulnerable LGBT young people," said Shannon Minter, legal director at NCLR, in a statement. "We look forward to more states joining California and New Jersey in preventing state-licensed therapists from engaging in discredited practices that offer no health benefits and put LGBT youth at risk of severe harm, including depression and suicide."

Therapists who engage in the practice and other proponents of the discredited therapy challenged the ban, which was signed into law by Gov. Jerry Brown in September 2012, in two cases, saying it violates the free speech of the practitioners and patients seeking such treatment. They argue a person's sexual orientation and gender identity can be changed by such treatments because they are not innate.

The Liberty Counsel, a conservative group that challenged the law, said they were disappointed by the Supreme Court's decision, but said the fight over bans on conversion therapy is not over.

"I am deeply saddened for the families we represent and for the thousands of children that our professional clients counsel, many of whom developed these unwanted attractions because of abuse of a pedophile," said Mat Staver, founder of Liberty Counsel, in a statement. "The minors we represent do not want to act on same-sex attractions, nor do they want to engage in such behavior. They are greatly benefiting from this counseling."

However, many leading health and psychological organizations, such as the American Psychological Association (APA) have concluded that sexual orientation cannot be changed and that efforts and treatments aiming to do so could be harmful. Bans on such efforts, the NCLR said, are "life-saving."

A similar ban was signed into law by New Jersey Gov. Chris Christie last year and has also been challenged in court. The New York State Assembly also passed a similar measure this month, but it was blocked by GOP leadership in the state Senate.