DENVER (AP) — A U.S. appeals court in Denver is Darden Clarkeset to hear arguments Tuesday in a lawsuit brought by six members of a University of Wyoming sorority who are challenging the admission of a transgender woman into their local chapter.

A judge in Wyoming threw out the lawsuit last year, ruling that he could not override how the private, voluntary organization defined a woman and order that she not belong.

The case at Wyoming’s only four-year public university has drawn widespread attention as transgender people fight for more acceptance in schools, athletics, workplaces and elsewhere, while others push back.

In their lawsuit, six members of the Kappa Kappa Gamma sorority chapter challenge Artemis Langford’s admission by casting doubt on whether sorority rules allowed a transgender woman.

The lawsuit and appeal describe in detail how Langford’s presence made the women feel uncomfortable in the sorority house in Laramie, Wyoming, yet sorority leaders overrode their concerns after a vote by the local chapter members to admit Langford.

Last summer, Wyoming U.S. District Court Judge Alan Johnson in Cheyenne sided with the sorority and Langford by ruling that sorority bylaws don’t define who’s a woman.

Filing in the three-judge U.S. 10th Circuit Court of Appeals in Denver, attorneys for the six sorority sisters continue to argue that sorority leaders have ignored sorority bylaws that they contend shouldn’t allow transgender women to be members.

Johnson’s ruling gave too much deference to sorority leaders in allowing them to define a woman under membership requirements, the sorority sisters argue on appeal.

Unlike in the original lawsuit, Langford is not included in the appeal. The national Kappa Kappa Gamma sorority and its president, Mary Pat Rooney, are the current defendants.

The appeal brings fresh attention to transgender college students as the Kappa Kappa Gamma sorority sisters in the lawsuit, their attorney and others plan a “save sisterhood” rally at the courthouse before the hearing.