An Oklahoma student is suing his state’s tax commission over its rejection of his request to put the words “I’m Gay” on his license plate.

According to The Wall Street Journal, Keith Kimmel argues that the denial violates his First Amendment rights, and that it represents a double standard because license plates with messages such as STR8FAN and STR8SXI have been approved in the past.

Last fall the tax commission turned down his request for the “I’m Gay” license plate, arguing that it violated an internal rule against tags that “may be offensive to the general public.”

The Oklahoma City Community College student filed a lawsuit in response to the denial last week, asking for his application to be granted. His attorney calls the state agency’s decision “viewpoint discrimination.”

In the interview below with The Oklahoman, Kimmel discusses the “double standard,” including plates referencing heterosexuality and sex toys that “slipped through," according to the state agency.