Gov. Jerry Brown has signed legislation requiring public schools to teach students about the contributions of gay and lesbian people, making California the first state to adopt such a measure.

The bill was cheered by gay rights advocates, and Brown said in a written statement Thursday that it "represents an important step forward for our state."

The legislation requires instruction in the social sciences to include the role and contributions of lesbian, gay, bisexual and transgender Americans, as well as people with disabilities and members of other cultural groups.

It would prohibit teaching from textbooks or other instructional materials that reflect adversely on people because of their sexual orientation.

"History should be honest," the Democratic governor said in a written statement. "This bill revises existing laws that prohibit discrimination in education and ensures that the important contributions of Americans from all backgrounds and walks of life are included in our history books."

Written by Sen. Mark Leno, D-San Francisco, the legislation was approved in the Legislature along party lines, with Democrats in favor and Republicans opposed.

Republicans and conservative groups railed against it again on Thursday.

Sen. Doug LaMalfa, R-Richvale, said Brown is "out of touch with what I think are still mainstream American values."

"That's not the kind of stuff I want my kids learning about in public school," LaMalfa said. "They've really crossed a line into a new frontier."

Leno's Senate Bill 48 is similar to a proposal that was approved by the Legislature in 2006 but vetoed by then-Gov. Arnold Schwarzenegger. Schwarzenegger, a Republican, argued that students were already protected from discrimination.

Existing California law requires public school instruction to include the contributions of women and other minorities, and it prohibits materials that reflect adversely on people because of race, gender or other characteristics. Leno's bill adds gay and lesbian people to that group.

"We are currently censoring a very important chapter of civil rights history about a community which has historically been demonized and discriminated against, and in recent decades has had success in fighting for its civil rights and first -class citizenship," said Leno, one of the first openly gay men to serve in the Legislature. "Excluding this from our textbooks and classrooms does a disservice to our students."

He said the law will result, for example, in lessons about gay rights advocates such as Harvey Milk, the slain San Francisco supervisor.

It could be years before textbooks include references to that history, however. The adoption of new instructional materials has been suspended until 2015 due to the state's poor financial condition. Advocates expected schools to use supplemental materials once the bill becomes law on Jan. 1.

Roland Palencia, executive director of the gay rights group Equality California, said in a prepared statement that the bill's signing "marks a monumental victory for the LGBT equality movement as the struggle of the diverse LGBT community in California will no longer be erased from history."

Meanwhile, Randy Thomasson, president of SaveCalifornia.com, an advocacy group that lobbied against the legislation, urged parents to remove their children from "immoral" public schools.

"It's time for parents who love their children to match their words with deeds and do what's necessary to get them out of the immoral government schools and into the safe havens of home schooling and church schools," he said in a prepared statement.

"People are already responding on our Facebook and saying they're pulling their children out," he said later Thursday afternoon. "Some people say they want to move out of the state."

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