By Josh Levs, CNN
(CNN) -- California Gov. Jerry Brown has signed a bill banning therapy aimed at turning gay kids straight, saying such efforts "will now be relegated to the dustbin of quackery."
"This bill bans non-scientific 'therapies' that have driven young people to depression and suicide," Brown tweeted.
The California Senate passed the bill in May. It will kick in on January 1.
The bill prohibits efforts to change the sexual orientation of patients under age 18.
The American Psychiatric Association says the potential risk of so-called "reparative therapy" is great, including depression, anxiety and self-destructive behavior. Therapists' alignment with societal prejudices against homosexuality may reinforce the self-hatred already felt by patients, the association says.
"The longstanding consensus of the behavioral and social sciences and the health and mental health professions is that homosexuality per se is a normal and positive variation of human sexual orientation," the association says.
After the bill passed the state Senate, Equality California spokeswoman Rebekah Orr praised the "right first step in making sure that young people are protected from these unscrupulous therapists who are really engaging in therapeutic deception that is based on junk science."
Equality California describes itself as the largest statewide advocacy group in California working for "full equality" for lesbian, gay, bisexual, and transgender people.
But the president of an organization that promotes reparative therapy, the National Association for Research & Therapy of Homosexuality, called the bill "another triumph of political activism over objective science."