check out lunarsight dot com/freq (sorry, I haven't made 5 posts yet so I can't post a URL...
it has lots of info about what things the different frequencies of brain waves are associated with. For example: 2.67Hz (also known as the "brown note") can supposedly makes you crap yourself because its the same frequency your intestine operates at. You obviously couldn't incorporate this into music because humans can only hear down to 20 hertz and most speakers wont even reproduce sound that low. But then again, why would you want to...

that was just a quick fun-fact... but seriously, you should check it out. I believe its something like 586 Hz that is associated with sex. And 586Hz is certainly well within the range of our hearing.