Hello!
I do know that USF does have a gay fraternity on campus - I am not sure exactly what it is called, but there is one. Not quite sure if they are still active, so you would need to check with the student organization office.
As for the national fraternities on campus, I am pretty sure they are not going to ask you if you are gay or not. That seems like such a crazy question - more than likely they will get to know you as a person, your interests, sports, etc etc. If there is a connection, I really do not see why your sexuality would be an issue. There are several chapters on campus that have great guys who I am pretty sure would accept your sexuality.
Hope this helps - I am in a sorority at USF, so PM me if you have any other questions.
