History professor George Chauncey testified today at a San Francisco federal court of appeals as a witness in a controversial case about Proposition 8, the measure that outlawed gay marriage in California in 2008.

According to a blog post by the Los Angeles Times, Chauncey spoke at length about the history of discrimination against homosexuals in the United States, explaining that laws in the 1950s encouraged the criminalization of gays and lesbians. Though anti-gay prejudice has lessened since that time, Chauncey said, it is still widespread today.

“The fear of homosexuals as child molesters or recruiters continues to play a role in debates over gay rights,” Chauncey said, the Los Angeles Times reported.

Because of the trial, Chauncey canceled the first meeting of his Monday seminar, “Selected Topics in Lesbian and Gay History.”