Bonk: The Curious Coupling of Science and Sex

Roach surveys early attempts to study sexual response, showing how scientists moved slowly and cautiously from animal models to human subjects. She opens with Albert R. Shadle’s mid-20th-century observations of porcupines and other animals, noting that many researchers began with nonhuman subjects to avoid social censure. Alfred Kinsey likewise filmed animal copulation before quietly turning his attention to human physiology.

She then turns to Robert Latou Dickinson, a Brooklyn Heights gynecologist who, beginning in 1890, collected detailed sexual histories from a wide range of women and conducted clinical observations that emphasized the role of the clitoris and challenged prevailing myths. Behaviorist John B. Watson argued that sex belongs in the laboratory as a subject of scientific study, but the scandal surrounding his affair with Rosalie Rayner blurred the line between rumor and evidence, showing how moral judgment can derail a career.

Roach traces the first instrumented human recordings to a 1932 study by Ernst Boas and Ernst Goldschmidt, whose cardiotachometer sessions with a married couple captured multiple female orgasms and significant changes in heart rate. By the 1950s, researchers like R. G. Bartlett were staging fully wired coitus studies in which scientific apparatus and technical language helped disguise the intimacy of what was being measured.

Kinsey’s secret attic sessions in the late 1940s were filmed without clinical instruments but produced highly detailed descriptions of arousal, from changes in the ears and nose to contractions in the anal sphincter; one notorious experiment measured ejaculation distance among paid male volunteers. Kinsey recruited subjects from many backgrounds (including gay men, amputees, and people with cerebral palsy) and noted that arousal could temporarily reduce pain, subdue the gag reflex, and place other limits on behavior. Next, Roach introduces William Masters and Virginia Johnson, who in 1954 launched a large, overtly clinical program with married heterosexual couples (and sex workers as early test subjects). Their 1966 book Human Sexual Response documented specific female and male physiological phenomena and helped normalize open discussion and partner communication, laying the groundwork for their later sex-therapy practice and for Masters’s eventual invention of an internal imaging device.

Roach describes Masters and Johnson’s “artificial coition” device: a thrusting plastic penis equipped with an internal camera and cold-light illumination to film women’s sexual responses from inside the vagina. In the laboratory, this setup recorded many complete cycles of sexual response, documented the source of vaginal lubrication as plasma transudation, and explored disputed questions such as cervical suction and vaginal tenting. Roach raises a central question: Which women can reach orgasm with a purely mechanical, straight-in/straight-out device, since many report that intercourse alone is not enough?

She summarizes Masters and Johnson’s conclusion that all orgasms are physiologically clitoral in origin and then contrasts their findings with a 1984 Colombian study by Heli Alzate and María Ladi Londoño. Their mapping of vaginal sensitivity (focused mainly on the anterior wall for most subjects) showed high orgasm rates among paid prostitutes during angled, firm digital stimulation but limited success when movements mimicked penile thrusting. The authors described thrusting alone as an inefficient way of inducing female orgasm.

Roach searches for the original penis-camera or its footage and learns that the device was likely dismantled and that related archival materials may have been destroyed. She attends a San Francisco event showcasing “sex machines” and observes contemporary mechanical devices that rely on repetitive thrusting while paying relatively little attention to clitoral stimulation. In a public demonstration, a large machine led a subject to climax only when a vibrator was added.

Roach notes how Masters and Johnson observed that men controlling the thrusting pattern often hinders female response; one machine user valued devices because they gave her complete control over speed, depth, and angle. The chapter concludes with Leonore Tiefer’s reminder that Masters and Johnson selected women who had a history of reliable coital orgasm, which helps explain their lab success, and with a nod to Marie Bonaparte’s anatomical measurements as another possible explanation for why some women reach orgasm from intercourse alone while others do not.

Roach traces the long-running debate over “intercourse orgasms” through Marie Bonaparte’s 1924 hypothesis that the distance between the clitoris and the vaginal opening predicts whether women climax from penetration alone. Bonaparte measured 243 women, categorizing them as téléclitoridiennes (women whose clitoris was more than 2.5 cm from the vaginal opening), mesoclitoridiennes (in whom the distance was around 2.5 cm), or paraclitoridiennes (in whom it was less than 2.5 cm), and argued that only the last group reliably reached orgasm through intercourse. Roach recounts Bonaparte’s unsuccessful attempt to surgically relocate her clitoris (the Halban-Narjani operation) in hopes of improving her sexual response.

Despite these invasive measures, Roach notes that contemporary advice literature from the 1920s through the 1930s, such as Theodoor van de Velde’s work, already promoted positions and techniques that increased clitoral contact, including woman-on-top postures and cunnilingus. Robert Latou Dickinson’s medical atlas similarly emphasized mechanical factors like pubic-bone pressure, range of motion, and the benefits of women controlling the movement.

Roach then follows mid-century and later developments. Alfred Kinsey’s 1953 survey reported that only about a third of women climaxed easily during intercourse, typically with direct clitoral stimulation. His findings provoked backlash in the 1950s, including Arnold Kegel’s counterclaims that focused on the vagina’s role in orgasm. Roach describes prevailing medical norms of the period—premarital pelvic exams and even the use of Pyrex tubes to address hymenal concerns—as evidence of how poorly female anatomy was understood in practice.

Physiologist Roy Levin proposed that sensitivity around the female urethral glans may help explain differences in intercourse outcomes. He lamented the lack of funding for basic research on female sexual physiology, suggesting that anatomical structure may effectively determine what kinds of stimulation work best. Later, Kim Wallen reanalyzed Bonaparte’s data, finding a strong statistical relationship that supported a simple “rule of thumb” about clitoral-vaginal distance and likelihood of orgasm (68). Wallen proposed that women who climax from intercourse alone may form an anatomically distinct subgroup. Roach closes by returning to the theme of agency: Kinsey’s work linked orgasm outcomes to active participation and control of movement, while Wallen’s interviews echoed that many women who climaxed during intercourse emphasized their own motion over a partner’s thrusting.