Brandon McInerney of Oxnard is accused of shooting Larry King, a gay classmate he thought was flirting with him, and his attorneys have argued McInerney was so humiliated by King's flirtation that it provoked him to kill his classmate, the Los Angeles Times reported Thursday.
Gay rights advocates have called the argument a classic "gay panic" defense.
Such panic defenses have been used in more than 45 cases nationwide, Equality California, a San Francisco group that advocates civil rights for gay and transgender people, said.
Prosecutors have sometimes chosen to reduce charges because of the difficulty of facing a "gay panic" defense in certain parts of the country, the group said.
In 2006 the California Legislature passed a law intended to weaken the use of panic defenses, giving judges the power to admonish jurors that a victim's sexual orientation should not influence deliberations.
Legislators and advocacy groups say they are gratified to see the jury instruction invoked.
"We can't restrict the free speech rights of the defense and the ability of a defendant to mount their defense," Sally Lieber, the former assemblywoman who wrote the 2006 law, said. "But the judge should instruct juries that a person's gender or sexual ID is not an invitation to assault or murder."