Every attempt to prove that humans have some kind of "sixth sense" shows it to be complete BS. But we have all sorts of "extra" senses that we either never use or don't notice when we do.
That being said:
Ovulating women can sense snakes and gays:
http://www.telegraph.co.uk/news/newstopics/howaboutthat/9132222/Women-who-have-just-finished-ovulating-are-best-at-spotting-snakes.html
http://healthland.time.com/2011/06/24/is-he-gay-ovulating-women-can-tell/
Hope that counts.
Ismael