First-graders at a California school celebrated Harvey Milk Day last week by learning about marriage equality.

Eric Ross, the author of new children’s book My Uncle’s Wedding, spoke to 40 six and seven-year-olds at a San Francisco elementary school.

Milk, who was assassinated in 1978, was a gay rights campaigner and the first openly gay man to be elected to public office in California. His birthday, May 22nd, has been designated a special day.

Ross said: “It was an honour to read My Uncle’s Wedding to the kids. I wish all schools had a more inclusive curriculum that didn’t censor history or current events.”

He added that an LGBT-inclusive curriculum would stop discrimination and help LGBT young people.

“Hopefully people will learn the value that we bring to society,” he said. “And hopefully students that struggle with their own sexual orientation or identity will be less likely to commit suicide when they see that diversity is something that should be celebrated.”

A new state bill aims to make the teaching of gay history compulsory in California.

The bill, SB 48, has already been passed by the Senate. Its full name is The FAIR (Fair, Accurate, Inclusive and Respectful) Education Act.

To pass, it must now win full state Assembly approval and be signed into law by governor Jerry Brown.

It would require schools to ensure that lesbian, gay, bisexual and trans people are recognised in text books and ban “discriminatory” materials.

California law already requires schools to highlight the contributions of women, African-Americans, Mexican Americans and entrepreneurs, among others.

This week, conservative critics complained about a gender diversity lesson held at another California elementary school.

Students in all grades at Oakland’s Redwood Heights Elementary learned about acceptance of gender diversity through lessons which used examples of animals such as transgender clownfish and single-sex geckos.