Attorney General Eric Holder (AP Photo/Manuel Balce Ceneta)

The U.S. Justice Department is suing an Oklahoma university, charging that school officials discriminated against a professor who changed gender during her time working there.

Rachel Tudor was hired as a tenure-track assistant professor in the English department at Southeastern Oklahoma State University in 2004, after applying as a man with a traditionally male name, according to the lawsuit  filed Monday. Then in 2007, according to the lawsuit, Tudor told school officials that she planned to transition from male to female during the academic year, took the name Rachel, and began wearing women’s clothes and a traditionally female hairstyle.

U.S. Attorney General Eric H. Holder Jr. announced in December that federal prohibitions against sex discrimination include protections based on gender identity.

[DOJ: Transgender people can’t be discriminated against at work]

Sean Burrage, who was not president at the time of the complaint but now leads the school, said in a statement: “Southeastern Oklahoma State University is committed to diversity and equal employment opportunities.  The University is confident in its legal position and its adherence to all applicable employment laws; however, due to the litigation, Southeastern has been advised by the Attorney General’s Office not to discuss any specifics concerning this matter.

“We will allow the legal system to run its course, while we direct our focus and energy on our top priority, that of educating our students.’’

The lawsuit alleges that a human resources staffer, who was not named, called Tudor and warned her that the school’s vice president for academic affairs, Douglas McMillan, had asked whether Tudor could be fired because the “transgender lifestyle” offended his religious beliefs.

Jane McMillan, director of the university’s counseling center and Douglas McMillan’s sister, told Tudor to be careful because some people were openly hostile to transgender people, and that Douglas McMillan considered them a “grave offense to his [religious] sensibilities,” the lawsuit says.

Tudor’s application for tenure was denied by a dean and McMillan without any reason given, the lawsuit claims, unlike an application by a male faculty member in the English department at the same time who was given guidance on how to improve his ultimately successful application.

Tudor filed a federal discrimination complaint.

Tudor was given the Faculty Senate Recognition Award for Excellence in Scholarship for the 2010-2011 academic year and was fired in May 2011 for failing to obtain tenure.

“By standing beside Dr. Tudor, the Department of Justice sends a clear message that we are committed to eliminating discrimination on the basis of sex and gender identity,” Holder said in a release.  “… And we will continue to work tirelessly, using every legal tool available, to ensure that transgender individuals are guaranteed the rights and protections that all Americans deserve.”

Harper Jean Tobin, director of policy for the National Center for Transgender Equality, said in a statement that it was “shocking that the leadership of a state university would, as this suit alleges, engage in such an elaborate scheme to push out a faculty member solely because she is transgender. And it is heartening that the Justice Department is willing to take on a state school school over this.”

The Oklahoma Attorney General’s Office will be representing the university.

Tudor did not immediately respond to messages seeking comment.

Jennifer Jenkins contributed to this report.