Gay rights groups praised California governor Jerry Brown Monday after the US state became the first to ban a form of therapy designed to change the sexual orientation of minors.
Doctors are now barred from performing so-called "reparative therapy" which experts say can cause psychological harm to youngsters, including driving them to having suicidal thoughts.
"These practices have no basis in science or medicine, and they will now be relegated to the dustbin of quackery," Brown said on his Twitter feed, after signing the ban into law at the weekend.
"This bill bans non-scientific 'therapies' that have driven young people to depression and suicide," he added.
Under the law doctors cannot provide therapy that seeks "to change behaviors or gender expressions, or to eliminate or reduce sexual or romantic attractions or feelings toward individuals of the same sex."
The law will come into force on January 1.
Lesbian, gay, bisexual and trans-gender (LGBT) rights groups had lobbied hard for California to pass the legislation, and were quick to praise the governor.
"Thank you @JerryBrownGov for signing #SB1172 into law and protecting #LGBT youth from psychological abuse!" tweeted The Trevor Project, which provides suicide prevention services to the LGBT community.
The Human Rights Campaign sent Brown a petition with nearly 50,000 signatures ahead of a midnight Sunday deadline for the governor to sign the bill into law, along with other pieces of legislation.
"LGBT youth will now be protected from a practice that has not only been debunked as junk science, but has been proven to have drastically negative effects on their well-being" said its head, Chad Griffin.
"We commend Gov. Brown for putting children first, and call on all states to take California's lead on this issue," he added, quoted by the San Francisco Chronicle.