The Stripper's Secret

Unlike their sisters in the animal kingdom, human females don't openly advertise their ovulation. But even without a human version of the baboon's bright pink behind, signs of fertility sneak out, according to several studies. Subconsciously, women dress more provocatively and men find them prettier when it's prime time for conception. And a report from the University of New Mexico demonstrates that the cyclic signs have economic consequences.

Psychologist Geoffrey Miller and colleagues tapped the talent at local gentlemen's clubs and counted tips made on lap dances. Dancers made about $70 an hour during their peak period of fertility, versus about $35 while menstruating and $50 in between. Read on >>