From a WHO YOU LOVE school assignment

"Heterosexual: People who love or are attracted to other people of the opposite gender."

Then, you may ask, "If there are more than two genders, what is the opposite gender?"
Seek no more. The answers is right here on THE GENDER WHEEL (with mouseover explanations for those not in the know). If you're not satisfied: press F5!
Upcoming improvements: all 80 Facebook genders, only one impossibly huge wheel, more representative colours.