The bill, passed on a party-line vote, adds lesbian, gay, bisexual and transgender people as well as people with disabilities to the list of groups that schools must include in the lessons. It also would prohibit material that reflects adversely on gays.
Democratic Assemblyman Tom Ammiano of San Francisco says SB48 is crucial because of the bullying that happens to gay students. Republicans called it a well-intentioned but ill-conceived bill and raised concerns that it would indoctrinate children to accept homosexuality.
"This bill will require California schools to present a more accurate and nuanced view of American history in our social science curriculum by recognizing the accomplishments of groups that are not often recognized," said Assembly Speaker John Perez, the first openly gay speaker of the California Assembly.
Assemblyman Tim Donnelly, a Republican from Twin Peaks, said he was offended as a Christian that the bill was being used to promote a "homosexual agenda" in public schools.
"I think it's one thing to say that we should be tolerant," Donnelly said. "It is something else altogether to say that my children are going to be taught that this lifestyle is good."
California law already requires schools to teach about women, African Americans, Mexican Americans, entrepreneurs, Asian Americans, European Americans, American Indians and labor. The Legislature over the years also has prescribed specific lessons about the Irish potato famine and the Holocaust, among other topics.
SB48 would require, as soon as the 2013-2014 school year, the California Board of Education and local school districts to adopt textbooks and other teaching materials that cover the contributions and roles of sexual minorities.
The legislation leaves it to local school boards to decide how to implement the requirement. It does not specify a grade level for the instruction to begin.
Opponents argued that such instruction would further burden an already crowded curriculum and expose students to a subject that some parents find objectionable. Assemblyman Chris Norby, R-Fullerton, said the bill micromanages the classroom.
"Our founding fathers are turning over in their graves," Donnelly said.
The bill's author, Sen. Mark Leno, D-San Francisco, said he hopes Brown will sign his bill. He dismissed arguments that the bill promotes certain sexual behaviors and said it removes censorship in textbooks.
"Bottom line, it's only beneficial to share with students the broad diversity of the human experience and that our democracy protects everyone," he said.
Before the Assembly vote, Perez pointed to a few contributions of gay people, including Friedrich von Steuben, one of George Washington's military advisers who fled Prussia after he was hounded as a homosexual.
Von Steuben is credited with being one of the fathers of the Continental Army and teaching essential military drills.
Some churches and conservative family groups warned the bill will drive more parents to take their children out of public schools.
"This sexual brainwashing bill would mandate that children as young as 6 years old be told falsehoods — that homosexuality is biological, when it isn't, or healthy, when it's not," said Randy Thomasson, president of SaveCalifornia.com.
The Assembly passed the bill on a 49-25 vote.