A same-sex marriage supporter waves a rainbow flag in front of the US Supreme Court (Photo credit: SAUL LOEB/AFP/Getty Images)

SACRAMENTO (CBS SF) — California could soon become the first state to ban the “gay panic” defense in violent crimes against LGBT individuals.

With Gov. Jerry Brown’s signature, the bill would prohibit people to use the argument that a violent act was triggered by the knowledge or perception of a victim’s sexual orientation as an attempt to downgrade a murder charge to manslaughter.

The LGBT Bar Association and the advocacy group Equality California both say the law would be the first of its kind in the country.

“Gay panic” defense predates to the 1920s when a psychiatrist coined the term to describe patients who he said were gay, but refused to admit it, according to a legal review published last fall in the Southwestern Law Review.

The review claims criminal defense attorneys starting using gay panic in the courtroom during the 1960s to argue that their clients panicked, then killed when a gay person made an unwanted sexual advance.

“Gay and trans panic defense strategies are problematic because they seek to capitalize on conscious and unconscious bias against gays and trans individuals,” co-author Cynthia Lee wrote.

The American Bar Association also passed a resolution last August recommending that courts instruct juries to ignore the victim’s gender or sexual orientation in its deliberations.

Attorney General Kamala D. Harris co-sponsored the bill with Assemblymember Susan Bonilla. It passed in the state Assembly last week by a 58 to 15 vote after passing though the Senate with a vote of 25 to 9.