How Sex Works

by Dr. Sharon Moalem

  Professor Devendra Singh: D. Singh and P. M. Bronstad, “Female Body Odour Is a Potential Cue to Ovulation,” Proc Biol Sci 268, no. 1469 (2001): 797–801.

  Dr. Ivanka Savic: I. Savic, H. Berglund, and P. Lindstrom, “Brain Response to Putative Pheromones in Homosexual Men,” Proc Natl Acad Sci USA 102, no. 20 (2005): 7356–7361.

  Dr. Savic followed up: H. Berglund, P. Lindstrom, and I. Savic, “Brain Response to Putative Pheromones in Lesbian Women,” Proc Natl Acad Sci USA 103, no. 21 (2006): 8269–8274.

  “Heterosexual males: Y. Martins, G. Preti, C. R. Crabtree, T. Runyan, A. A. Vainius, and C. J. Wysocki, “Preference for Human Body Odors Is Influenced by Gender and Sexual Orientation,” Psychological Science 16 (2005): 694–701.

  “Our study can’t answer: Dr. Ivanka Savic, quoted in P. Barry, “Clue to Sexual Attraction Found in Lesbian Brain,” New Scientist, May 8, 2006.

  A recent study published: S. S. Young, B. Eskenazi, F. M. Marchetti, G. Block, and A. J. Wyrobek, “The Association of Folate, Zinc, and Antioxidant Intake with Sperm Aneuploidy in Healthy Non-Smoking Men,” Human Reproduction 23, no. 5 (2008): 1014–1022.

  But where does tall: N. G. Jablonski, Skin: A Natural History (Berkeley: University of California Press, 2006).

  According to Alan Slater: Alan Slater, quoted in A. Gosline, “Babies Prefer to Gaze upon Beautiful Faces,” New Scientist, September 6, 2004.

  Slater believes babies: Ibid.

  But as Charles Darwin: C. Darwin, The Descent of Man, and Selection in Relation to Sex: The Concise Edition (New York: Plume, 2007).

  Well, in 2007 researchers: A. C. Little, C. L. Apicella, and F. W. Marlowe, “Preferences for Symmetry in Human Faces in Two Cultures: Data from the UK and the Hadza, an Isolated Group of Hunter-Gatherers,” Proc Biol Sci 274, no. 1629 (2007): 3113–3117; A. C. Little et al., “Symmetry Is Related to Sexual Dimorphism in Faces: Data Across Culture and Species,” PLoS ONE 3, no. 5 (2008): 2106.

  Dr. Anthony Little made: Dr. Anthony Little, quoted in R. Highfield, “Symmetry Really Is Sexy, Say Scientists,” Telegraph, November 15, 2008.

  Another small but interesting: R. Thornhill, S. W. Gangestad, and R. Comer, “Human Female Orgasm and Mate Fluctuating Asymmetry,” Animal Behaviour 50, no. 6 (1995): 1601–1615.

  “We don’t think women: Randy Thornhill, quoted in D. Concar, “Sex and the Symmetrical Body,” New Scientist, April 22, 1995.

  But that won’t stop: Ibid.

  In the masterfully compiled book: A. Taschen, ed., Aesthetic Surgery (London: Taschen, 2005).

  Şerafeddin Sabuncuoğlu was: I. Basagaoglu, S. Karaca, and Z. Salihoglu, “Anesthesia Techniques in the Fifteenth Century by Şerafeddin Sabuncuoğlu,” Anesth Analg 102, no. 4 (2006): 1289.

  According to the American Society: For statistics on yearly cosmetic procedures in 2007, see the American Society for Aesthetic Plastic Surgery, http://www.surgery.org/press/news-release.php?iid=491.

  It’s not just Botox injections: A. M. Munhoz et al., “Aesthetic Labia Minora Reduction with Inferior Wedge Resection and Superior Pedicle Flap Reconstruction,” Plast Reconstr Surg 118, no. 5 (2006): 1237–1250.

  Perhaps when girls as young: A. Lynch, M. Marulaiah, and U. Samarakkody, “Reduction Labioplasty in Adolescents,” J Pediatr Adolesc Gynecol 21, no. 3 (2008): 147–149.

  An Australian study says: G. Rhodes, L. W. Simmons, and M. Peters, “Attractiveness and Sexual Behavior: Does Attractiveness Enhance Mating Success?” Evolution and Human Behavior 26 (2005): 186–201.

  And a British study: K. K. Kampe, C. D. Frith, R. J. Dolan, and U. Frith, “Reward Value of Attractiveness and Gaze,” Nature 413, no. 6856 (2001): 589.

  “Meeting a potential good friend: Knut Kampe, quoted in H. Muir, “Beautiful People Spark a Brain Reaction,” New Scientist, October 10, 2001.

  There has long been: D. Blum, Sex on the Brain: The Biological Differences Between Men and Women (New York: Viking, 1997).

  “Most men are very visual: Dr. Daniel Amen, quoted in “Use Your Brain to Have Hotter Sex,” Today, http://www.msnbc.msn.com/id/16673923/page/2/.

  And there have certainly: S. Hamann, R. A. Herman, C. L. Nolan, and K. Wallen, “Men and Women Differ in Amygdala Response to Visual Sexual Stimuli,” Nat Neurosci 7, no. 4 (2004): 411–416.

  Another 2004 study: M. L. Chivers, G. Rieger, E. Latty, and J. M. Bailey, “A Sex Difference in the Specificity of Sexual Arousal,” Psychol Sci 15, no. 11 (2004): 736–744.

  Then, in 2007, researchers: T. M. Kukkonen, Y. M. Binik, R. Amsel, and S. Carrier, “Thermography as a Physiological Measure of Sexual Arousal in Both Men and Women,” Journal of Sexual Medicine 4 (2007): 93–105.

  Also in 2007, Kim: H. A. Rupp and K. Wallen, “Sex Differences in Viewing Sexual Stimuli: An Eye-Tracking Study in Men and Women,” Hormones and Behavior 51, no. 4 (2007): 524–533.

  Surprisingly, Rupp said: Dr. Heather Rupp, quoted in “A Selection of Kinsey Institute Research,” http://www.indiana.edu/~kinsey/research/summary-photos.html.

  By the way, paying: R. O. Deaner, A. V. Khera, and M. L. Platt, “Monkeys Pay Per View: Adaptive Valuation of Social Images by Rhesus Macaques,” Curr Biol 15, no. 6 (2005): 543–548.

  “Flirting is a way of testing: Arthur Aron, quoted in B. Luscombe, “The Science of Romance: Why We Flirt,” Time, 2008.

  Regardless of how: Charles Darwin, The Expression of the Emotions in Man and Animals (Chicago: University of Chicago Press): 372.

  In fact, a new study: S. M. Hughes, M. A. Harrison, and G. G. Gallup Jr., “Sex Differences in Romantic Kissing Among College Students: An Evolutionary Perspective,” Evolutionary Psychology 5, no. 3 (2007): 612–631.

  In an article in: C. Walter, “Affairs of the Lips,” Scientific American, January 2008.

  Chapter 4: Let’s Talk About Sex

  Among the Yungar people: A. J. Hobday, L. Haury, and P. K. Dayton, “Function of the Human Hymen,” Med Hypotheses 49, no. 2 (1997): 171–173.

  According to Jelto Drenth: J. Drenth, The Origin of the World: Science and Fiction of the Vagina (London: Reaktion Books, 2005).

  The Trotula, a medieval medical text: M. H. Green, The Trotula: An English Translation of the Medieval Compendium of Women’s Medicine (Philadelphia: University of Pennsylvania Press, 2002).

  These sham virginity procedures: E. Sciolina and S. Mekhennet, “In Europe, Debate over Islam and Virginity,” New York Times, June 11, 2008; B. Crumley, “The Dilemma of Virginity Restoration,” Time, July 13, 2008.

  According to the Kama Sutra: A. Daniélou, The Complete Kama Sutra: The First Unabridged Modern Translation of the Classic Indian Text (South Paris, ME: Park Street Press, 1994).

  A study from the Archives: J. A. Adams, A. S. Botash, and N. Kellogg, “Differences in Hymenal Morphology Between Adolescent Girls With and Without a History of Consensual Sexual Intercourse,” Arch Pediatr Adolesc Med 158, no. 3 (2004): 280–285; Adams, J. A. “Guidelines for medical are of children evaluated for suspected sexual abuse: an update for 2008” Curr Opin Obstet Gynecol, 20(5), (2008) 435–441. McCann, J., Miyamoto, S., Boyle, C., and Rogers, K., (2007) “Healing of hymenal injuries in prepubertal and adolescent girls: a descriptive study.” Pediatrics, 119(5), e1094–1106. D. Holtzman and N. Kulish, “Nevermore: The Hymen and the Loss of Virginity,” J Am Psychoanalytic Assoc 47 (1999): 1461–1464.

  Oxytocin and vasopressin: Hammock, E. A. “Gene regulation as a modulator of social preference in voles.” Adv Genet, 59, (2007) 107–127.

  Fascinating research: Walum, H., Westberg, L., Henningsson, S., Neiderhiser, J. M., Reiss, D., Igl, W., et al. “Genetic variation in the vasopressin receptor 1a gene (AVPR1A) associates with pair-bonding behavior in humans.” Proc Natl Acad Sci U S A, 105(37) (2008): 14153–14156.

  “Men with two: H. Walum, quoted in S. Vedantam, “Study Links Gene Variant in Men to Marital Discord,” Washington Post, September 2, 2008.

  “There are many: H. E. Fisher, Why We Love: The Nature and Chemistry of Romantic Love (New Yo
rk: Holt, 2004).

  “An intricately coordinated: B. R. Komisaruk, C. Beyer, and B. Whipple, The Science of Orgasm (Baltimore, MD: Johns Hopkins University Press, 2006).

  But as Dr. Elisabeth Lloyd: E. A. Lloyd, The Case of the Female Orgasm: Bias in the Science of Evolution (Cambridge, MA: Harvard University Press, 2005).

  Baker said the images: Robin Baker, quoted in Michael Wedeman, “Sperm Wars: The Science of Sex,” Journal of Sex Research, reprinted at http://findarticles.com/p/articles/mi_m2372/is_/ai_20746731.

  Lloyd, in fact: E. A. Lloyd, The Case of the Female Orgasm: Bias in the Science of Evolution (Cambridge, MA: Harvard University Press, 2005); D. Symons, The Evolution of Human Sexuality (New York: Oxford University Press, 1979).

  “Females Get the Nerve Pathways: Elizabeth Lloyd, quoted in D. Smith, “A Critic Takes On the Logic of the Female Orgasm,” New York Times, May 17, 2005.

  “Recreational sex: J. M. Diamond, Why Is Sex Fun? The Evolution of Human Sexuality (New York: HarperCollins, 1997).

  With all the attention focused: A. F. Kiroglu, H. Bayrakli, K. Yuca, H. Cankaya, and M. Kiris, “Nasal Obstruction as a Common Side-Effect of Sildenafil Citrate,” Tohoku Journal of Experimental Medicine 208, no. 3 (2006): 251–254.

  In his treatise: Hippocratic Writings, translated by J. Chadwick, W. N. Mann, E. T. Withington, and I. M. Lonie. (New York: Penguin Classics, 1984).

  The definitive Sanskrit text: Daniélou, The Complete Kama Sutra. Dhall, “Adolescence: Myths and Misconceptions.”

  Even twentieth-century American: R. Chalker, The Clitoral Truth: The Secret World at Your Fingertips (New York: Seven Stories, 2002).

  Maxine Davis, author of: Davis, M. Sexual Responsibility in Marriage. (New York: Dial Press, 1963).

  “No matter how tired: C. B. S. Evans, N. Haire, and R. L. Dickinson, Sex Practice in Marriage (New York: Emerson, 1935).

  As Dr. Whipple: F. Addiego, E. G. Belzer, J. Comolli, W. Moger, J. D. Perry, and B. Whipple, “Female Ejaculation: A Case Study,” Journal of Sex Research 17 (1981): 13–21.

  In a 1988 study: M. Zaviačič, A. Zaviačičova, I. K. Holomáň, J. Molčan, “Female Urethral Expulsions Evoked By Local Digital Stimulation of the G-Spot: Differences in the Response Patterns,” Journal of Sex Research 24 (1988): 311–318.

  That study was followed by: C. A. Darling, J. K. Davidson Sr., and C. Conway-Welch, “Female Ejaculation: Perceived Origins, the Grafenberg Spot/Area, and Sexual Responsiveness,” Arch Sex Behav 19, no. 1 (1990): 29–47.

  No less a sexual science celebrity: E. Grafenberg, “The Role of Urethra in Female Orgasm,” International Journal of Sexology 3(1950): 144–145.

  In 2002, the British Board of Film: B. Arndt, “Women and the UFO of Sex,” The Sydney Morning Herald, April 19, 2003.

  Philadelphia gynecologist: A. K. Ladas, B. Whipple, and J. D. Perry, The G Spot and Other Recent Discoveries About Human Sexuality (New York: Holt, Rinehart, and Winston, 1982).

  The vulva and vagina were: Ibid.

  The most recent study of: F. Wimpissinger, K. Stifter, W. Grin, and W. Stackl, “The Female Prostate Revisited: Perineal Ultrasound and Biochemical Studies of Female Ejaculate,” Journal of Sex Medicine 4, no. 5 (2007): 1388–1393.

  Sex educator Deborah Sundahl: D. Sundahl, Female Ejaculation and the G-Spot (Alameda, CA: Hunter House, 2003).

  One thing is sure: Wimpissinger et al., “The Female Prostate Revisited.”

  When I spoke: Personal interview with Beverly Whipple.

  “Begin with clitoral: Ibid.

  As one sufferer said to: Judith Reichman, “Help! What Do I Do About ‘Honeymoon Cystitis’?” Today, http://www.msnbc.msn.com/id/9225687/.

  “Obviously, it is difficult: N. B. McCormick, “When Pleasure Causes Pain: Living with Interstitial Cystitis,” Sexuality and Disability 17 (2004): 7–18.

  “Whipple and Perry hypothesized: Ladas, A. K., Whipple, B., and Perry, J. D. The G Spot and Other Recent Discoveries About Human Sexuality. (New York: Holt, Rinehart, and Winston, 1982).

  Professor Itzhak Ofek: See the press release: www. eurekalert.org/pub_releases/2008–01/afot-cra011008.php; Ofek, I., Goldhar, J., Zafriri, D., Lis, H., Adar, R., and Sharon, N. “Anti-Escherichia coli adheson activity of cranberry and blueberry juices.” (1991) N Engl J Med, 324(22), 1599.

  But it may be: S. A. Robertson, W. V. Ingman, S. O’Leary, D. J. Sharkey, and K. P. Tremellen. “Transforming Growth Factor Beta—A Mediator of Immune Deviation in Seminal Plasma,” J Reprod Immunol 57, no. 1–2 (2002): 109–128.

  This theory is supported: R. B. Ness, D. A. Grainger, “Male Reproductive Proteins and Outcomes,” Am J Obstet Gynecol, 198, 6 (2008): 620el–4; C. A. Koelman, A. B. Coumans, H. W. Nijman, II Doxiadis, G. A. Dekker, and F. H. Claas, “Correlation Between Oral Sex and a Low Incidence of Preeclampsia: A Role for Soluble HLA in Seminal Fluid?” J Reprod Immunol 46, no. 2 (2000): 155–166.

  Chapter 5: Come as You Are

  One of the best explications: M. Ridley, The Red Queen: Sex and the Evolution of Human Nature (New York: Perennial, 2003).

  Cheryl Chase, executive director: Sally Lehrman, “Going beyond X and Y,” Scientific American; May 2007.

  In December 2006, Santhi: Katie Law, “The Indelicate Art of Gender Testing,” Inkling Magazine, January 17, 2007, http://www.inklingmagazine.com/articles/gender-testing/.

  The magazine New Scientist: A. George, “Teenagers Trapped in the Wrong Body,” New Scientist, 2007.

  So what is GID?: Ibid.

  A new study: E. K. Bentz, L. A. Hefler, U. Kaufmann, J. C. Huber, A. Kolbus, and C. B. Tempfer, “A Polymorphism of the CYP17 Gene Related to Sex Steroid Metabolism Is Associated with Female-to-Male But Not Male-to-Female Transsexualism,” Fertil Steril 90, no. 1 (2008): 56–59.

  Dr. Eric Vilain: S. Lehrman, “Going beyond X and Y,” Scientific American, May 20, 2007.

  Chapter 6: Let It Be

  In 1972, Linda Wolfe: Personal interview.

  Evolutionary biologist Paul Vasey: P. L. Vasey, “Function and Phylogeny: The Evolution of Same-Sex Sexual Behavior in Primates,” Journal of Psychology and Human Sexuality 18 (2007): 215–244.; P. L. Vasey, “Sex Differences in Sexual Partner Acquisition, Retention, and Harassment During Female Homosexual Consortships in Japanese Macaques,” American Journal of Primatology 64 (2004): 397–409;

  As Vasey succinctly states: Paul Vasey, quoted in Stephanic Chasteen, “Gender Scientists Explore a Revolution in Evolution,” Stanford Report, February 19, 2003, http://news-service.stanford.edu/news/2003/february19/aaassocialselection219.html.

  When I asked her: Personal interview with Linda Wolfe.

  Macacques are certainly not: J. Roughgarden, Evolution’s Rainbow: Diversity, Gender, and Sexuality in Nature and People (Berkeley: University of California Press, 2004).

  My discipline teaches: Joan Roughgarden, quoted in J. Lehrer, “The Gay Animal Kingdom,” Seed Magazine, June 2006, http://seedmagazine.com/news/2006/06/the_gay_animal_kingdom.php.

  Male big horn sheep: Ibid.

  Cataloging animal homosexuality: B. Bagemihl, Biological Exuberance: Animal Homosexuality and Natural Diversity (New York: St. Martin’s Press, 1999).

  And, if you have any doubt: C. W. Moeliker, “The First Case of Homosexual Necrophilia in the Mallard Anas Platyrhynchos (Aves: Anatidae),” DEINSEA 8 (2001): 243–247.

  “If you’re looking for: Robin Dunbar, quoted in G. Vines, “Queer Creatures,” New Scientist, August 7, 1999.

  “One plausible explanation: Ibid.

  “Same-sex sexuality: Ibid.

  “Although the first reports: Ibid.

  “As biologist Valerius Geist: Ibid.

  When it comes to humans: K. J. Verweij et al., “Genetic and Environmental Influences on Individual Differences in Attitudes Toward Homosexuality: An Australian Twin Study,” Behav Genet 38, no. 3 (2008): 257–265.

  One of the most prominent: J. M. Bailey and R. C. Pillard, “A Genetic Study of Male Sexual Orientation,” Arch Gen Psych 48, n
o. 12 (1991): 1089–1096.

  With the research: Simon LeVay, quoted in Neil Swidey, “What Makes People Gay?” Brain Research Institute, August 12, 2005, http://www.bri.ucla.edu/bri_weekly/news_050812.asp.

  Dr. Camperio-Ciani’s latest study: A. Camperio-Ciani, F. Iemmola and S. R. Blecher, “Genetic Factors Increase Fecundity in Female Material Relatives of Bisexual Men as in Homosexuals,” J Sex Med 6, 2 (2008): 449–455; F. Iemmola, A. Camperio-Ciani, “New Evidence of Genetic Factors Influencing Sexual Orientation in Men: Female Fecundity Increase in the Maternal Line,” Arch Sex Behavior [Epub ahead of print]; A. Camperio-Ciani, F. Corna, and C. Capiluppi, “Evidence For Maternally Inherited Factors Favouring Male Homosexuality and Promoting Female Fecundity,” Proc Biol Sci 271, no. 1554 (2004): 2217–2221.

  “We have finally solved: Andrea Camperio-Ciani, quoted in A. Coghlan, “Survival of Genetic Homosexual Traits Explained,” New Scientist, October 13, 2004.

  “We think of it: Simon LeVay, quoted in Ibid.

  “It helps to answer: Dean Hamer, quoted in T. Osborne, “Bisexuality Passed On by ‘Hyper-Heterosexuals,’” New Scientist, August 15, 2008.

  “Our findings are only one piece: Camperio-Ciani, quoted in Coghlan, “Survival of Genetic Homosexual Traits Explained.”

  “Genetics is not determining: Andrea Camperio-Ciani, quoted in “How Bisexuality Is Passed On in the Genes,” New Scientist, August 20, 2008.

  “I haven’t found one:” William Reiner, quoted in N. Swidey, “What Makes People Gay?” Boston Globe, August 14, 2005.

  “Exposure to male hormones: Ibid.

  More evidence that prenatal hormone: T. J. Williams et al., “Finger-Length Ratios and Sexual Orientation,” Nature 404, no. 6777 (2000): 455–456.

  Chapter 7: Tainted Love

  A team of researchers: A. K. Chaturvedi, E. A. Engels, W. F. Anderson, and M. L. Gillison, “Incidence Trends for Human Papillomavirus-Related and-Unrelated Oral Squamous Cell Carcinomas in the United States,” J Clin Oncol 26, no. 4 (2008): 612–619.

  “What we do know: Lesley Walker, quoted in M. Day, “Oral Sex-Related Cancer at 30-Year High,” New Scientist, 2008.