Marquette graduate Cameron Sanchez says at first, he did not take this seriously.
"But then I went online and saw it had 18,000 signatures," said Sanchez.
The petition is on a website called "The American Society for the Defense of Tradition, Family and Property," also known as TFP.
John Ritchie, TFP Student Action Director refused to talk to us on camera, but sent us a statement though email that read in part, promoting Pride Prom, "...is like promoting drugs for those who suffer from a drug addiction."
"They're hurtful, but they're not Marquette. I mean Marquette's motto is 'Be The Difference,'" Sanchez added.
"None of my theology classes did they teach anything that wasn't accepting and love and so I think it was disappointing to see," said Paige Gardner, Marquette University Alumnus.
Sanchez and Gardner recently set up a fundraiser called "Black out Hate" at bars near Cathedral Square.
"We treated this organization as an inspiration and not as our opposition," said Sanchez.
More than $2,200 was raised for the Cream City Foundation, which provides resources for Milwaukee's LGBT community.
"It was kind of exciting to see people hear other people's stories and interact with people they may not have," said Gardner.
Ritchie with TFP claims "Many Marquette students and alumni have signed the petition," and, "...so far, the university has not answered our concerns."
Marquette University leaders sent us a statement that reads in part, "We support our LGBT community..." and, "...we also take seriously The Catechism of the Catholic Church's note that people should not rush to "rash judgment" of their neighbor.""
They add pride prom will go on as planned at Union Hall later this month, and all Marquette Students are welcome to attend.