MIDDLEBORO — A lawsuit was filed in federal court Wednesday against the town and school system for forbidding a middle school student from wearing a shirt with the message “There are only two genders,’’ saying the prohibition violated his First Amendment right to free speech.

“Students do not shed their constitutional rights at the schoolhouse gate,’’ the lawsuit reads in part.

The suit, Morrison v. Town of Middleboro, was filed in U.S. District Court on behalf of Nichols Middle School student Liam Morrison, 12, who was told to remove the shirt by school officials on March 21. He was subsequently told to remove a different shirt that read “There are (censored) Genders’’ on May 5.

The issue has drawn international attention, with Liam and his supporters arguing that he has the right to express his views and the schools claiming his message was discriminatory.

The suit was filed by attorneys representing the Alliance Defending Freedom and Massachusetts Family Institute. The suit specifically names the town, the School Committee, Superintendent of Schools Carolyn Lyons and Acting Middle School Principal Heather Tucker. 

“This isn’t about a T-shirt; this is about a public school telling a seventh grader that he isn’t allowed to hold a view that differs from the school’s preferred orthodoxy,” said Alliance Defending Freedom Senior Counsel Tyson Langhofer. 

“Public school officials can’t censor Liam’s speech by forcing him to remove a shirt that states a scientific fact,’’ Langhofer said. “Doing so is a gross violation of the First Amendment.”

The school district has countered through its attorneys that the school has and will continue to prohibit shirts with “messages likely to be considered discriminatory, harassing and/or bullying to others, including those who are gender nonconforming by suggesting that their sexual orientation, gender identity or expression does not exist or is invalid,’’ according to a letter written by attorney Kay Hodge of the legal firm Stoneman, Chandler & Miller of Boston.

The shirt incident came to public light when Liam spoke at the April 27 School Committee meeting to detail what had happened when he wore the “two genders’’ shirt. He said he was told to remove it, and when he refused, was sent home. 

He has said his message was not threatening or harmful but simply an expression of his belief.

The schools, Langhofer said, have adopted a differing viewpoint, “that a person’s subjective identity determines whether a person is male or female, not a person’s sex. ‘’

The school has a speech policy, he wrote, that “permits students to express viewpoints supporting their view of gender identity but forbids students from expressing a contrary view.’’

The morning of the meeting when Liam spoke, a group of adults stood outside the middle school with signs reportedly reading “There are only two genders’’ and “Keep woke politics out of our schools.’’ 

The next day, signs were held by others in support of transgender students.

Lyons has not directly commented on the T-shirt or the lawsuit. But she did say at the April 27 School Committee meeting that “the dividing line for me as this district’s leader is when all students are not protected, when all students are not accepted for who they are and are told, either directly or indirectly, that they don’t belong here in Middleboro.’’

She has also argued that “children were caught in the crossfire of a debate that doesn’t belong at their feet, it doesn’t belong at their schoolhouse. This is unacceptable to me.’’

The alliance described itself as non-profit legal organization “commited to protecting religious freedom, free speech, parental rights and the sanctity of life.’’ The institute describes itself as “dedicated to strengthening the family and affirming the Judeo-Christian values upon which it is based

Lyons and Tucker did not immediately respond Wednesday to a request for comment. Select Board Chair Mark Germain and Town Administrator James McGrail said they had no comment on the suit at this time.