In case there was any doubt, Harvard University has officially banned sex between professors and students.

Until last week, Harvard had a policy that discouraged such relationships but did not explicitly ban them. But on Thursday, the 379-year-old Ivy League university banned professors from engaging in "sexual or romantic relationships with undergraduates," the Los Angeles Times reported.

According to the university, the old policy failed to specifically address staff's expectations of what's appropriate between students and professors. The committee that spearheaded the change made it clear the new policy is within the norm.

"We are certainly not the first university to institute such a ban, and I think most universities expect their faculty to refrain from such relationships, whether or not they formally ban them," committee head Alison Johnson told the Los Angeles Times.

The ban comes as Harvard among other universities are under investigation by the U.S. Education Department for its handling of sexual assault reports, Bloomberg News reported.

Yale University and the University of Connecticut already banned relationships between faculty and students, according to Bloomberg. Other schools, however, maintain a not-so-strict ban.

That includes the University of Southern California, which "strongly discourages" such sexual relationships but did not outright ban them in its 2014 handbook, according to the LA Times.

USC officials provided the newspaper with the handbook but did not expand on the subject.

At Harvard's campus in Massachusetts, however, there was little doubt about what's considered appropriate between students and teachers.

In fact, some students already assumed sex with professors was already banned.

"I thought this was already codified," 22-year-old Harvard senior Leonie Oostrom, who is studying human development and regenerative biology, told Bloomberg News.