A new book has suggested several reasons why humans are one of the only species that use kissing as a method of facilitating reproduction.

“The Science of Kissing” by Sheril Kirshenbaum not only shares the history behind some of our kissing-related habits, but also reveals the anatomy of the lip-lock and how swapping spit might help us select our sexual partners.

“The New York Post” recently posted more than a few factoids about the puckering process – including the fact that six major muscles are responsible for our mouths' seemingly simple make-out position – and gave us a little insight into how this first-base act often leads to stealing home plate.

According to studies discussed in the aforementioned book, women use kissing as a way to figure out whether or not the man attached to the mouth is worth going all the way with. Up close and personal contact with the oral region can reveal hygiene and health levels, and there supposedly is a way to tell how strong a man's immune system is by his smell.

Make sure you hit the right spot.

Make sure you hit the right spot.

And apparently men are able to pass on bits of testosterone to women via their saliva at the same time women are trying to decide whether or not to fornicate with their kissing partner. So it's a two-way street.

I suppose this means whether or not either party gets lucky depends on how fast one of these two seemingly innate character – and sexual ability – judgments comes into play.

All I ask is that the man with whom I'm about to make out, and the tongue attached, is clean, dextrous, and can make me come. Whether or not his cock is compatible with my vaginal needs can be determined later.

LA Weekly