A 17-year-old senior at Sequoyah High School, Chris Sigler, claimed his principal shoved and verbally harassed him last week for wearing a t-shirt in support of establishing a Gay-Straight Alliance (GSA) club.

A teacher had told Sigler he could not wear his homemade shirt, which said “GSA: We’ve Got Your Back,” but he wore it to school anyway. When he refused an order to remove the shirt, Principal Maurice Moser ordered all students out of the classroom, except for him and his sister. The principle then grabbed Sigler’s arm, shoved him, and bumped him on the chest repeatedly while asking “Who’s the big man now?”

Sigler's family filed a report about the incident that afternoon with the Monroe County Sheriff’s Department.

“All I want is to have a GSA at my school to help stop the bullying against gays and lesbians and their friends who support them,” he said. “The shirt was a way to use my voice and show my support for the club. The way I was treated shows even more why we need a GSA here.”

The American Civil Liberties Union and the ACLU of Tennessee sent a letter to the school district on Tuesday demanding that students’ rights to free speech be protected in the classroom.

“It is totally unacceptable that a young man who was peacefully exercising his First Amendment rights would have his speech shut down by the public school principal,” said Hedy Weinberg, executive director of the ACLU of Tennessee. “Last week’s incident clearly illustrates the hostile environment LGBT students face at Sequoyah High School. Given this context, it’s especially important that supportive voices like Sigler’s can be heard in order to overcome the school’s resistance to a GSA.”

It is not the first time the ACLU has defended student's rights to wear shirts in support of LGBT rights.

An eighth-grade Louisiana student who was sent home from school for wearing a shirt that said “Some Kids are Gay. That’s OK” also received support from the ACLU.

The ACLU has defended student's right to criticize homosexuality as well.

The ACLU of Illinois defended the free speech rights of Neuqua Valley High School students who wore shirts that said “Be Happy, Not Gay.” The 7th U.S. Circuit Court of Appeals ruled in early March that a “school that permits advocacy of the rights of homosexual students cannot be allowed to stifle criticism of homosexuality.”