Parents of a transgender child are challenging a California district’s decision to remove a sex-ed instruction about gender identity from a student’s public high school curriculum.

The American Civil Liberties Union of California, the National Center for Lesbian Rights and the Transgender Law Center filed a federal lawsuit Monday in Sacramento against the district.

They argue that transgender students should not be treated as second-class citizens under California law and that the district’s policy of barring transgender students from classes on gender identity violates their constitutional rights.

The district’s transgender policy is part of a statewide effort by some districts to accommodate students whose gender identity does not match their biological sex.

In the case before the U.S. District Court in San Francisco, a district court judge said last year that a transgender student should not have to sit through a class on gender-identity issues that was taught in the name of gender identity and gender expression.

The ACLU said in a statement Monday that the suit was an example of the transgender community’s efforts to protect its students’ constitutional rights and protect its civil rights.

“California is a beacon for transgender equality and is poised to lead the way in the United States in ensuring transgender students can thrive in the classroom and receive access to comprehensive, inclusive and respectful instruction,” said Emily Bazelon, the ACLU of Northern California’s executive director.