Since the beginning of the semester, more than 40 members of a Tufts University sorority have ditched the group in protest over then national office delayed its decision on whether to approve membership for a transgender student.

Though Alpha Omicron Pi eventually extended a membership offer to the student, Harper Hopkins, the sorority’s national office first hesitated, saying it lacked a policy on admitting transgender students.

Hopkins initially accepted the offer and joined AOII but soon quit, describing the sorority’s initial treatment as an issue of “systemic inequality and structural violence” and decrying AOII’s “oppressive policies and behavior.”

In an emailed statement to Heat Street, a spokeswoman for the Alpha Omicron Pi International Fraternity said: “The chapter will continue to recruit members who embrace diversity, are passionate about social action, and are dedicated to maintaining their high standards of excellence. … Alpha Omicron Pi believes that all individuals are unique, with inherent worth and dignity, and should be treated with respect.”

More than half the sorority’s members joined Hopkins in defecting AOII—including even the AOII chapter president for Tufts, Kristin Reeves, who declined to comment for this article.

“It didn’t really seem fair,” Reeves told the Boston Globe this week. “By them saying we couldn’t give her a bid because they don’t have a policy? That’s basically them taking a stance and having an unofficial policy.”

Administration has also thrown its support behind Hopkins.

“Tufts University has been named one of the best universities in the country for LGBTQ students by a number of organizations,” said spokesman Patrick Collins. “We believe that students should be bale to join the Greek Life organization with which they identify.”

The Tufts students who remained at AOII have pushed for the sorority to be more inviting to transgender students. At the sorority’s national summer convention this summer, the Tufts chapter intends to introduce several bylaw amendments to the AOII bylaws.

Specifically, the Boston Globe reported, Tufts AOII chapter will push to change the word “women” to “female-identifying” in the sorority’s bylaws, also mandating training focused on microaggressions, sexual assault, and diversity.

Jillian Kay Melchior writes for Heat Street and is a fellow for the Steamboat Institute and the Independent Women’s Forum.