Sex Ed: Talking Smack

What kissing means for men and for women.

Kiss of Life

Romantic love has three components—romance, attachment, and sexual arousal—and kissing activates all three, says Helen Fisher, author of Why Him? Why Her? Both men and women also kiss to assess genetic compatibility. That's why kissing someone new can create sparks—or cause a budding romance to wither on the branch. We determine compatibility largely via scent, but saliva exchange may well play a role as well. Maybe that's why 66 percent of women and 59 percent of men have experienced a first kiss with a new person that instantly killed the attraction.

What He's Thinking

• WIFE SWAB
  The testosterone in saliva—and stimulation of our highly sensitive lips and tongues—may help trigger sex drive. Men exploit this, using kissing to induce sexual desire in women. Men may also unconsciously use kissing to assess the level of estrogen in a woman's saliva to determine her stage in the ovulation cycle and her fertility.
• TASTE TEST
  Men are more likely than women to initiate wet, open-mouthed, saliva-exchanging tongue kissing—since their senses of taste and smell are less acute, they need bigger, sloppier samples to gather enough information to assess compatibility.
• READ MY LIPS
  The lips are nature's mood ring: They flush darker when a person is aroused, signaling receptivity. Men are attracted to women with naturally large lips, which signal arousal and openness. Since lip plumpness peaks at age 14 in females, full lips also connote youth and good health.
• KISS AND MAKE UP
  Men instinctively use kissing to smooth over conflicts—with great success.
• FIRE AT WILL
  Men are more willing to have sex without kissing.

What She's Thinking

• MALE BONDING
  Kissing drives up levels of oxytocin, which promotes attachment and bonding. The novelty of kissing someone new may release dopamine, which fosters romantic love. Women exploit this, using kissing to promote bonding. Women also kiss to assess the health of the relationship: Kissing is a good barometer of how happy a couple is.
• DEATH TO SMOOCHY
  Kissing evolved as a mate- assessment tool—a way for men and women to try each other out, to literally taste each other before committing. Women prefer demure, closed-mouth kisses—since their senses of taste and smell are acute, they don't need a lot to assess compatibility.
• THROUGH THICK AND THIN
  On a man, too much plump indicates a lack of masculinity and dominance. Women prefer men with medium-size lips: thick enough to convey compassion and friendliness, but not so large as to appear feminine.
• THE WRONG EMBRACE
  Women incorrectly believe kissing is not a good way to reconcile after a fight.
• LADY IN WAITING
  Most women say they wouldn't have sex without kissing.