A US appeal court has blocked a first-of-its-kind California law that bans therapy aimed at turning gay youngsters straight.
A three-judge panel of the 9th US Circuit Court of Appeals issued an emergency order putting the law on hold until the court could hear full arguments on whether the measure was constitutional.
The law was set to take effect on January 1.
Licensed counsellors who practise so-called "reparative therapy" and two families who say their teenage sons have benefited from it sought the injunction after a lower court judge refused the request.
The law, which was passed by the state legislature and signed by governor Jerry Brown in the autumn, said therapists and counsellors who used "sexual orientation change efforts" on clients under 18 would be engaging in unprofessional conduct and subject to discipline by state licensing boards.
The appeal court's order prevents the state from enforcing the law while a different three-judge panel considers if the measure is in breach of the First Amendment rights of therapists and parents.
Liberty Counsel president Mathew Staver, whose Christian legal aide group is representing reparative therapy practitioners and recipients in an action seeking to overturn the law, welcomed the appeal court's decision to delay its implementation.
"This law is politically motivated to interfere with counsellors and clients. Liberty Counsel is thankful that the 9th Circuit blocked the law from going into effect," Mr Staver said. "This law is an astounding overreach by the government into the realm of counselling and would have caused irreparable harm."
Backers of the ban say the state is obligated to outlaw reparative therapy because the practice puts young people at risk and has been rejected by every mainstream mental health association.
After signing the law - SB1172 - the governor called the therapies it would outlaw "quackery" that "have no basis in science or medicine".