I really got a kick out of this recent XKCD. It's obviously a joke, but I think it's also onto something. Lots of things are sexy when you really immerse yourself in them. I'm always amazed about this when I'm writing for anthologies. The themes can be all over the map, yet when I take the time to sink in, there's always something really hot about them.
Sex is fundamental. It's inside of every part of human experience.