I'm not trying to be a prick but I can't be the only one who finds the term "heterosexual" to be excessively long for something that should be quite simple?

Hetero means two different things, and sexual means, well, exactly what you think it means. We are going to use this to describe the most common sexual orientation? This sounds like a disease. If I wanted to sound like a brave scientist, I would say something like; "Sorry to inform you, but our findings show that you are suffering from heterosexual. I'm afraid you will have to live with this for the rest of your life. There is no cure. I'm sorry."