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Odd Facts About Kissing

A kiss is not just a kiss.

  • A quick romantic kiss burns about two to three calories. A more passionate kiss burns five or more calories, depending on the duration and intimacy of the kiss.
  • The average person spends about 20,160 minutes of his or her life kissing.
  • The condition and appearance of a potential partner’s teeth play a determining factor in a woman’s decision to kiss someone or not.
  • Men are more likely to initiate kissing before sex. Women are more likely to initiate kissing after sex.
  • Women use the intensity and frequency of kissing to evaluate a man’s suitability for short-term relationships as well as judging the potential of a short-term relationship evolving into a long-term relationship. Men use kissing, especially in short-term relationships, to increase the likelihood of having sex.
  • Mucous membranes inside the mouth are permeable to hormones such as testosterone. Through open-mouth kissing, men introduce testosterone into a woman’s mouth. Testosterone is absorbed through the mucous membranes in the woman’s mouth and increases arousal and the likelihood that she will engage in reproductive behavior.
  • Men prefer open-mouth kissing with tongue contact when kissing short-term partners to increase the probability of mating.
  • Open-mouth kissing promotes salivary exchange. Saliva contains salts, minerals, and other substances that cause breath odor to change as women progress through their menstrual cycle. These changes regulate a woman’s receptivity to procreative activities.
  • Prostitutes avoid kissing clients on their mouths to reduce the likelihood of bonding.
  • Men seeking short-term relationships are more apt to leave shortly after copulation to reduce the likelihood of bonding.
  • Kissing provides information about a person’s health. The taste and the smell of an individual's mouth can signal health issues. Women seek partners who can provide security for them and their children. Unhealthy men are less likely to be able to provide long-term security. Men seek women who are healthy enough to bear and raise children. Unhealthy women are less likely to bear healthy children.
  • Men, more than women, use kissing in an attempt to end fights.


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Hughes, S. M. & Harrison, M. A. (2007). Sex differences in romantic kissing among college students: An evolutionary perspective. Evolutionary Psychology 5, 612-631.

McCabe, M. P. & Collins, J. K. (1984). Measurement of depth of desired and experienced sexual involvement at different stages of dating. Journal of Sex Research, 20, 377-390.

McCann, A. & Bonci, L. (2001). Maintaining women's oral health. Dental Clinical North America, 45, 571-601.

Pause, B. M., Sojka, B., Krauel, K., Fehm-Wolfsdorf, G., and Ferstl, R. (1996). Olfactory information processing during the course of the menstrual cycle. Biological Psychology, 44, 31-54.

Rosenberg, M. (2002). The science of bad breath. Scientific American, 286, 72-78.

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