The American Civil Liberties Union (ACLU) of Minnesota and the advocacy group Gender Justice filed a lawsuit against the Anoka-Hennepin School District and its school board on Monday.

The lawsuit alleges that the district violated the constitutional and civil rights of LGBTQ students when it banned a transgender boy from using the boys' locker room at Coon Rapids High School.

The teen was on the boys' swim team and had used the boys' locker room for the majority of the 2015-2016 season before he was banned.

A 17-year-old transgender boy in Minnesota was banned from his high school's boys' locker room, despite using it for months, according to a lawsuit filed against the district.

The American Civil Liberties Union (ACLU) of Minnesota and the advocacy group Gender Justice filed a lawsuit against the Anoka-Hennepin School District on Monday on behalf of the boy, who has only been identified as N.H.

The lawsuit accuses the school district of violating the constitutional and civil rights of LGBTQ students.

The 17-year-old boy had joined the boys' swim team at Coon Rapids High School as a freshman in 2015 and used the boys' locker room for the majority of the 2015-2016 season, according to the lawsuit.

In February 2016, with three swim meets left in the season, the school board told the student he would no longer be allowed to use the boys' locker room when the season finished, and would instead use a segregated locker room for transgender students, an ACLU press release said.

Days after the decision was made, the teen was hospitalized for "mental health concerns," and later hospitalized a second time "following a public debate during which the board heard testimony from members of the public affiliated with hate groups," according to court documents.

Read more: A GOP lawmaker withdrew support for an anti-LGBTQ bill after his daughter called him out

"They used their power, and went out of their way to create a problem where there wasn't a problem to begin with," the boy's mother, identified as J.H., told CBS Minnesota. "They conspired to isolate my [son], and ultimately, their actions altered the course of his life."

A spokesman for Anoka-Hennepin School District told INSIDER that N.H. is no longer a student within the district, and that he left in 2017. It is unclear where he's attending school now.

The spokesman said: "The use of restrooms and locker rooms are determined on a case-by-case basis. The goal is to ensure that all students feel safe and comfortable. Plans for accommodation for restroom and locker room use are made in consultation with school building administrators, the Title IX coordinator, and superintendent in compliance with state and federal law. This approach is consistent with guidance from the National School Boards Association and the Minnesota School Boards Association. Providing privacy for all students is an important consideration."

INSIDER has contacted the ACLU for comment.