An HIV-related sex discrimination lawsuit could set a precedent for LGBT rights and is gaining support among Democratic members of the U.S. Congress, CNN reports.

Last summer, Matthew Christiansen, a creative director for Omnicom Group, filed a $20 million lawsuit alleging that a supervisor repeatedly made lewd, inappropriate remarks such as accusing him of having AIDS because he is gay. Christiansen, who is in fact gay and HIV positive, feared that his supervisors had access to his medical records and that coworkers would shun him.

The lawsuit also alleges the supervisors drew sexually explicit pictures and “created a pervasive hostile workplace atmosphere” for Christiansen.

Title VII of the Civil Rights Act of 1964 prohibits, among other things, sex discrimination in the workplace. Christiansen lost the case at district level when the judge said that sexual orientation doesn’t fall under the anti-discrimination protections. He is appealing the decision.

Christiansen’s lawyer argued that “at the heart of this appeal is whether Title VII protects those males and females whose sexual orientation is not heterosexual,” according to CNN.

Last week, 128 Democratic members of Congress submitted a friend-of-the-court brief in support of Christiansen. The brief argues that sexual orientation discrimination should be included in the interpretation of civil rights law. This is the first time that this claim has been made in a federal appeals court.

If Christiansen wins his appeal, it could have a large effect on the workplace rights of LGBT people.

To read the entire 38-page court case filed last summer, click here.