HARPSWELL, Maine — The parents of a charter school student have sued their local school district, alleging discrimination because it denied their son the opportunity to play for the middle school basketball team.

In a lawsuit, filed Nov. 9 in federal court, Harpswell residents Wesley and Carrie Withers say their son was unlawfully discriminated against by SAD 75 — a district including Bowdoin, Bowdoinham, Harpswell and Topsham — because officials wouldn’t allow him to try out for the Mt. Ararat Middle School team.

The student, who isn’t identified in court documents because he is a minor, has attended Harpswell Coastal Academy since 2012, when it opened as one of Maine’s first public charter schools. The suit, filed in Portland, states that he played for the Mt. Ararat team last year, in seventh grade, but that a change in school policy barred him from trying out again this year.

Now, the parents are asking a federal judge to intervene by ruling the new policy is a violation of Maine’s charter school laws and the student’s constitutional rights.

Under Maine law, charter school students may participate in an extracurricular activity in their home school district if the charter that student attends doesn’t offer that particular activity. It requires the written approval of the superintendent, who can deny the request only if the team or group does not have “capacity” for the charter student.

This past July, the SAD 75 board adopted a new policy on charter school students and their access to interscholastic extracurriculars.

The spat arose from a section of that policy which states that charter students would be allowed on a team only if there is room, or “capacity,” on the team after every interested student in the district schools has an opportunity to try out. The district says capacity is reached if enough students from the district school try out for the team. For example, if 13 Mt. Ararat students try out for the basketball squad, the team is full and there’s no room for a charter school student.

The Witherses and HCA argue that all students living in a district should have the chance to try out. Whether they make the team, club or organization should be based on their ability, not on how many kids turned out. Filling the slots with students who attend the school without giving charter school students a chance to try out is discriminatory, they said.

SAD 75, in its legal response to the lawsuit, argued that the Witherses chose to send their son to HCA knowing that it didn’t have certain extracurricular programs, and thus he does not have the “unconditional right to try out for one of the 13 available spots on the Mt. Ararat basketball team.”

The district argued that would mean excluding a student who attends Mt. Ararat.

“We strongly disagree with the view that the policy is discriminatory,” said SAD 75 Superintendent Bradley Smith in an email Friday. “Maine statute allows for denial if the district lacks ‘capacity.’ It’s worth noting that we have had HCA students join our teams when we have capacity, and our district cooperated with HCA by providing transportation and special education during their first year.”

In September, as the dispute was building but before the lawsuit, then-Acting Maine Department of Education Commissioner Tom Desjardin chimed in, sending a letter to Smith.

“The department’s interpretation of capacity is that all public charter school students who wish to take part in these activities should have an equal opportunity to do so,” he wrote. “For example, in the case of a baseball player, the decision as to whether the student is chosen for the team should be based solely on their ability to play baseball in comparison to the others trying out.”

Desjardin sided with the family and charter school, saying, “it is very likely that Maine courts will give deference to this interpretation if and when a case comes before it.”

DOE spokeswoman Anne Gabbianelli said Friday the department’s position hasn’t changed under the new leadership of Commissioner Bill Beardsley.

The Maine Charter School Commission also takes this view, according to Executive Director Bob Kautz.

“Both sides feel what they’re doing is the best thing for their students,” Kautz said, adding that this dispute would “clarify some questions we’ve had” about the relationship between public charters and local school districts.

The family hopes the court resolves the dispute before teams are selected on Monday, according to their attorney. Tryouts have already taken place, but if the ruling comes down before Monday, then their son will have a last-minute chance to try out for a spot.

A message left for the Withers family was not returned Friday. Their suit also points out that the family pays taxes in Harpswell, and thus the school department has no financial justification for not allowing their child to participate.

The charter school is required to reimburse the school district for a “reasonable share” of the school district’s costs associated with having the charter student participate in the activity. Parents of charter students are required to pay any fees associated with participation, the same as noncharter parents.

“While we would like to include all students, it is simply not possible,” Smith said. “I’m certainly sorry that we don’t have room for this student from the Harpswell Coastal Academy. However, if we were to name him to our school team, which is already at capacity, he would bump one of our other eighth graders who does not attend a private or charter school.”

Follow Nick McCrea on Twitter at @nmccrea213.