Calif. Sen. Ted Lieu sponsored a bill outlawing therapy to convert minors from gay to straight in California. The bill was signed into law by Gov. Jerry Brown this past weekend. (Rich Pedroncelli/AP)

Therapy aimed at changing the sexual orientation of minors who say they are gay has been outlawed in California, the first state to adopt such legislation. California Gov. Jerry Brown announced he had signed the bill on Sunday.

The bill's sponsor, Calif. State Sen. Ted Lieu, said the so-called " conversion therapy," "sexual orientation therapy," "reparative therapy," or "sexual orientation change efforts" - amounts to "psychological child abuse."

"No one should stand idly by while children are being psychological abused, and anyone who forces a child to try to change their sexual orientation must understand this is unacceptable," Lieu said in a statement released Sunday.

Supporters of the bill, which takes effect Jan. 1, included gay rights group as well as health organizations such as California's Board of Behavioral Sciences and California Psychological Association. Critics have argued the therapy can cause emotional damage to patients.

But opponents of the Lieu bill had denounced it as infringing on parents' rights.

"Your bill will turn California into a nanny state by usurping the civil rights of parents who support their child's right to receive therapy for unwanted same-sex attractions, especially when that child has been sexually molested. This smacks of fascism and ex-gay bashing," the California-based group Parents and Friends of Ex-Gays and Gays wrote in an open letter to Lieu in August.

Earlier this year, " What Would You Do?" tested people's reactions to witnessing a counselor urging a teen to seek treatment for his sexual preference. One couple sided with the counselor, while others objected to his work.

Watch the full scene below and watch an all-new episode of "What Would You Do?" Friday at 9 p.m. ET.