You've got to kiss a lot of frogs to find your prince, as the saying goes. New research suggests the cliché is true on an evolutionary level.
Women, who tend to be pickier about romantic entanglements than men, also care more about kissing in the first phases of a relationship, suggesting that make-outs may weed out dudswomen are especially attuned to the importance of kissing during fertile phases of the menstrual cycle.
Kissing also may have evolved to keep romantic pairs bonded, or to increase arousal prior to sex. If kissing is a way to assess mates, the pickiest people should place the highest importance on kissing.
This appears to be the case: Women, who take on the risk of gestating, birthing and caring for a child when they have sex, are generally more choosy about mates than men. "At different times in the relationship, [kissing] is used for different things," Wlodarski said