Has the original poster ever been inside of a high school before? It's ridiculous to be even semi-openly gay and then get offended over every little comment. It's just the result of living in a sheltered world.
Gay people, black people, white people, women, men, soldiers, civilians, youth, the elderly, fat people, thin people, smart people, and stupid people will be attacked for who they are. It's life, and if you haven't been attacked for some reason or another, then welcome to the planet Earth. Enjoy your stay.
It doesn't show character to bring this up with the admissions. It just shows that you're easily offended, which is NOT a good trait for someone who will be working with sick, angry, tired, stressed people of all shapes, colors, and personalities. You aren't going to be changing the guy's mind on what he thinks about gay people, you aren't going to get him kicked out, and you may not even be able to prove he did anything. If you're going to be working with the public, it's time to put on big boy pants and get ready for the real world, where this is going to be coming up all the time, and you're going to be dealing with it constantly.
Nowhere am I saying that you should hide yourself from the world and repress who you are. But the guy didn't commit a crime, and for all intents and purposes, did nothing more than express an opinion verbally. He didn't even accuse you of being a "***", just asked if you were. Against you, that's freedom of speech. The school can't do anything about it, and in almost every case where this comes up, there won't be anything you can do about it. So the only real solution is to learn to deal with it now by getting a thicker skin, ESPECIALLY if you're not one to be afraid to express your sexuality openly.