JFUR: Ever watch Will & Grace? Like that.
Seriously, some folks look, talk, and act Gay. Whether or not they actually are, I don't care. Accept it, there is a society stereotype, and yes, some things make you appear gay. It's not just a single thing--it depends on context.
EX: Some folks can wear 2 earings and get away with it, while others... GAY.
I also agree that just because you look gay doesn't mean you are. If you don't like the fact that there is a stereotype, dress gay, and go out shouting "I am not gay". That should help.