A Missouri school district has indefinitely suspended a high school teacher after he showed students a 1960s film linking being gay to pedophilia.

Ken Simon, who taught history at Raymore Peculiar High School for 47 years, was just weeks from retirement when he was told he could not finish the year.

Simon showed the film in a law enforcement class made up mostly of seniors, Kansas City's WDAF-TV reported.

The 1961 film, titled Boys Beware, was produced by the Inglewood, California Police Department and the Inglewood Unified School District. In one of the film's scenarios, a man named Ralph attempts to lure a boy named Jimmy.

“What Jimmy didn't know was that Ralph was sick. A sickness that was not visible like Smallpox but no less dangerous and contagious. A sickness of the mind. You see, Ralph was a homosexual, a person who demands an intimate relationship with members of their own sex,” the film's narrator says.

“One never knows when the homosexual is about,” the narrator warns. “He may appear normal and it may be too late when you discover he is mentally ill.”

Simon said that he was using the film to show how attitudes have changed since the film was produced, but administrators rejected that argument.

More than 1,300 people have signed a petition asking the district to give Simon his job back.