Harvard University has instituted a total ban on professors having sex with undergraduate students, strengthening language it said didn't reflect its expectations on appropriate relationships between faculty members and students.

Harvard said in a statement released Thursday the change came as part of a formal review of its policy on Title IX, the federal civil rights law prohibiting sex discrimination in education.

The Faculty of Arts and Sciences Committee on Sexual Misconduct Policy and Procedures determined the university's language on "relationships of unequal status" was not strong enough.

"Therefore, the Committee revised the policy to include a clear prohibition to better accord with these expectations," Harvard said in its statement.

The university, which is based in Cambridge, just outside Boston, has about 2,400 faculty members and about 6,700 undergraduate students. Previously, its policy prohibited professors from having sex with students under their direct supervision. The policy now specifically bans professors and undergraduates from having any romantic or sexual involvements.

History professor Alison Johnson, who led the committee, said it spent last summer and fall consulting with students, faculty members and staff to get feedback.

"As part of this process, we thought a lot about the way that power dynamics can contribute to sexual harassment," Johnson said in an email. "We wanted to emphasize that the central characteristic of any relationship between a professor and an undergraduate in the College should be pedagogical."