Attorneys for Tirrell and co-plaintiff Iris Turmelle, 14, filed their lawsuit Friday to challenge the enforcement of the new law after Tirrell’s parents were told Thursday that she would no longer be welcome to soccer practice starting Monday because the new law, which takes effect this weekend, would exclude her from the team.

Under the new law, public schools that educate students in fifth through 12th grade and private schools whose students compete against public schools must declare their school sports and club track and field teams as either men’s or women’s teams, or as teams from both groups.

The law banning men from competing on women’s teams defines a student’s gender based on their unaltered birth certificate. If a birth certificate “does not appear to be original” or gender at birth is not indicated, the student must “provide other proof indicating the student’s gender at the time of birth” and bear all associated costs.

Supporters of the bill, which Republican Gov. Chris Sununu signed last month, said it would ensure safety and fairness in girls’ sports.

The plaintiffs argue that they pose no threat to their teammates, have no unfair advantage, and have a legal right to participate on school sports teams that correspond with their gender identity under Title IX and the equal protection principle of the 14th Amendment to the U.S. Constitution.

Although the Pemi-Baker Regional School District, where Tirrell attends school, has not yet adopted a policy detailing how it will comply with the new law, and state agencies have not provided guidelines on how to implement it, Superintendent Kyla A. Welch told the Boston Globe that her administration has concluded it has no choice but to begin enforcing the new law’s restrictions. Private parties could sue schools if they don’t, she noted.

The parties in the pending litigation had discussed a possible short-term agreement over the weekend that would allow the plaintiffs to continue to participate in their respective schools’ athletics events while the legal proceedings were ongoing, but attorneys for the state declined to sign such a contract.

Christopher G. Bond, general counsel for the New Hampshire Department of Justice, said Sunday that the attorney general’s office is tasked with defending properly enacted state laws in court, and that the office will not grant an injunction that would strike down any provisions of the law at issue in this case.

The plaintiffs filed an emergency motion last week asking the court to issue a temporary restraining order to prevent Tirrell and Turmelle from accessing “an important and unique educational program that cannot be duplicated or replaced,” a motion that led to Monday’s hearing.

Tirrell is a rising sophomore at Plymouth Regional and Turmelle is a rising ninth-grader at Pembroke Academy, a public high school. They and their respective parents are represented by three law firms that advocate for the rights of LGBTQ+ people: GLBTQ Legal Advocates & Defenders (GLAD), the American Civil Liberties Union of New Hampshire and the Goodwin Law Firm.

This is a breaking news story that will be updated.

Steven Porter can be reached at [email protected]. Follow him @Reporterporter.