I have seen a few outrageous papers during my time; I have to admit this ranks close to the top...
"Ovulatory cycle effects on tip earnings by lap dancers: economic evidence for human estrus?"
Read it here. I found out later that not surprisingly, this was a 2008 Ig Nobel prize winner.
One thing is for sure: everything in this world lends itself to scientific investigation, and especially the raucous adventures of promiscuous men and women. That is the beauty of science.