Apparently the first legislation of its kind nationwide, the bill passed the state Senate 22-15 Thursday, with all 14 Republicans opposed. The measure must be approved by the Assembly and Gov. Arnold Schwarzenegger, who has taken no position.
If passed, the textbook bill could have national implications because California often sets U.S. trends.
Republican state Sen. Bill Morrow said there was no reason for a textbook to point out the sexual orientation of historical figures when "their contribution to history has nothing to do with their sexual proclivities."
Advocates said subjects might include the 1978 assassination of San Francisco Supervisor Harvey Milk. Geoffrey Kors, executive director of Equality California, said textbooks might also specify the sexual orientation of well-known Americans such as writer Langston Hughes.
A national survey conducted last year by the Gay, Lesbian and Straight Education Network reported that 75 percent of homosexual students frequently overheard derogatory remarks at school. Advocates of the bill say more positive role models could reduce high suicide rates among gay and lesbian students.