Nearly every week I receive an email from at least one woman asking me what she needs to do to have an orgasm during intercourse, or worrying that something may be wrong with her because she can’t. Yet I rarely, if ever, receive the same question from men.The simple fact is that the male orgasm typically comes easily during sex and female orgasms do not. The late Dr. Alfred C. Kinsey, famous for interviewing thousands about their sex lives, declared that 75% of men ejaculate within two minutes of penetration in over half of their sexual encounters.It should come as no surprise, then, that researchers from the University of Chicago have declared that men reach orgasm during intercourse far more consistently than do women, and that three-fourths of men, but less than a third of women, always have orgasms.According to Drs. Kim Wallen and Elisabeth Lloyd who recently published a study in the Journal of Hormones and Behavior entitled “Female Sexual Arousal: Genital Anatomy and Orgasm in Intercourse,” there’s one striking difference between men’s and women’s ability to orgasm: female orgasmic ability develops more slowly over time and with less predictability.In fact, the researchers have found that, as a man moves from puberty to adulthood, his odds of ejaculating (and therefore, presumably, climaxing) increase from 5% to 100% within just 5 years. This increase appears to be much more gradual in women: According to Kinsey, a woman’s chances of experiencing orgasm slowly rise over the course of 25 years but never even approach 90%.This “orgasm discrepancy” between the sexes may help explain why, in the recently published National Survey of Sexual Health and Behavior, 85% of men said that their partner had experienced an orgasm during their most recent sexual event, while only 64% of women reported actually having had an orgasm.But why is the female orgasm so inconsistent during intercourse? For generations, it was widely believed that a woman who couldn’t orgasm as a result of intercourse had psychological inhibitions or was sexually frigid.Much of this misunderstanding goes back to the legacy of Freud, who could not reconcile himself with the powerful role of the clitoris in female sexual pleasure. Freud perpetuated the myth that the clitoris was an immature source of sexual pleasure, a mere launching pad for the more “mature” vaginal orgasm, which, of course, should be produced via genital intercourse.“With the change to femininity the clitoris should wholly, or in part, hand over its sensitivity and at the same time its importance to the vagina,” wrote Freud in the New Introductory Lectures on Psychoanalysis.Fortunately, today we are becoming more aware of the role of the clitoris as the powerhouse of the female orgasm. The clitoris has over 8,000 nerve fibers - more than any other part of the human body - and interacts with the 15,000 nerve fibers that service the entire pelvic area. In their landmark work, “A New View of a Woman's Body: A Fully Illustrated Guide,” the Federation of Feminist Women’s Health Centers identified 18 structures as part of the clitoris, both external and internal.Even what we think of as the G-spot may simply be a part of the clitoris. As science writer Natalie Angier describes in her book “Woman: An Intimate Geography” the area of soft tissue just inside the vaginal area, “the roots of the clitoris run deep, after all, and very likely can be tickled through posterior agitation. In other words, the G-spot may be nothing more than the back end of the clitoris.”In their recent study, Wallen and Lloyd analyzed years of data that support the notion that the distance between a woman’s clitoris and her vagina influences the likelihood that she will regularly experience orgasm solely from intercourse.According to Wallen and Lloyd, women who reported experiencing orgasm more regularly had a shorter distance between their clitoris and vagina - less than 2.5 centimeters - than did women who reported not experiencing, or less regularly experiencing, orgasm during intercourse.“Thus, some women may be anatomically predisposed to experience orgasm from intercourse, while the genital anatomy of other women makes such orgasms unlikely,” write the researchers.Why does this distance matter? A shorter distance provides for more stimulation of the external structures of the clitoris during intercourse, and may also reflect that the internal structures are more densely packed and pressing closer to the vagina, and therefore more receptive to sensation during intercourse.As Angier writes of the clitoral network, “Nerves are like wolves or birds: If one starts crying, there goes the neighborhood.”When you have a shorter distance between clitoris and vagina, you’re more likely to get those nerves howling. But regardless of the variation of this distance on a specific woman, Wallen and Lloyd’s study helps render the female orgasm less elusive (and hopefully more consistent) by showing us, from an anatomical perspective, why intercourse on its own may not consistently lead to female orgasm.As he neared the end of his life, Freud acknowledged his incomplete understanding of female sexuality and said, “If you want to know more about femininity, you must interrogate your own experience, or turn to the poets, or else wait until science can give you more profound and more coherent information.”Today, sexual science is finally providing us with the information and, hopefully, we’ll act upon it. By understanding the role of the clitoris in producing the female orgasm, and knowing that intercourse does not always directly stimulate the clitoris depending on its position, men and women need not fault themselves when intercourse fails to produce mutual satisfaction, but rather can focus on extending foreplay (and those activities we associate with foreplay) into fuller acts of love-making.I look forward to the day when I’ll stop receiving those emails.