A federal judge in San Francisco on Tuesday denied a request to postpone the January 1 start of California's ban on “ex-gay” therapy to minors.

Senate Bill 1172 outlaws therapies which promise to alter the sexual orientation of minors from gay to straight. Such practices are called “reparative” or “conversion” therapy. The measure was sponsored by state Senator Ted Lieu and signed into law by Governor Jerry Brown in October.

U.S. District Court Judge Kimberly Mueller concluded that the law “prohibits a therapeutic practice deemed unproven and potentially harmful to minors by ten professional associations of mental health experts.”

The lawsuit was filed by the National Association for Research & Therapy of Homosexuality (NARTH), which strongly opposed passage of the law. The organization is represented by the Christian conservative Liberty Counsel, which has a long record of opposing LGBT rights.

Mueller's ruling follows an opposite decision by Judge William B. Shubb, who sits on the same district bench.

On Monday, Shubb granted an injunction blocking California from enforcing the law but limited his ruling to the case's three plaintiffs, who are represented by the social conservative organization the Pacific Justice Institute.

Shubb said the law violates the First Amendment rights of mental professionals who practice “reparative” therapy, the AP reported.

Mueller also granted a motion by Equality California to defend the law in court alongside California Attorney General Kamala Harris. Equality California, the state's largest gay rights advocate, pushed for the law's passage.

“This law will put a stop to one of the most dangerous and discredited forms of discrimination against LGBT youth,” Equality California Executive Director John O'Connor said in a statement. “Every day that licensed therapists are permitted to engage in these dangerous and discredited practices is another day that our youth are placed at risk of depression, substance abuse, and attempted suicide. The state has a duty to protect minors from conduct by licensed heath care professionals that is both harmful and offers no benefit to health.”

The Los Angeles Times quoted UC Irvine Law School Dean Erwin Chemerinsky as saying the opposite conclusions will ultimately be decided by the 9th Circuit Court of Appeals.