Talk dirty to me

What Mary Roach won't do for a book! In her delicious "Stiff: The Curious Lives of Human Cadavers," Roach hung out with severed heads in a dissection lab, sniffed around a body farm (more politely known as a forensic anthropology facility) and studied smashed corpses donated for automobile-crash research -- all to aid her investigation of an aspect of existence most of us prefer to ignore.

Now, in "Bonk: The Curious Coupling of Science and Sex," Roach has chosen a topic that is perhaps the antithesis of death: our sexual physiology and psychology. Like "Stiff," "Bonk" (almost interchangeable titles, no?) is rich in dexterous innuendo, laugh-out-loud humor and illuminating fact. It's a compulsively readable, informative history of the scientific inquiry into the hows and wherefores of engorged tissues and sweaty palms, from Leonardo to Kinsey and on to Annie Sprinkle, including coverage of "artificial coition machines," panda porn, the challenges of conducting sex studies in Islamic countries and the workings of the orgasm in people with spinal cord injuries.

Roach contends that while the relationship between scientist and science can be tricky, that of the sexologist to sex is especially fraught. Views of sexual activity have always been colored by societal biases or shifting values: The Middle Ages attributed impotence and sterility to demonic forces; the Victorians had their moral take on the "excessive venery" of masturbation; 1950s America had its marriage manuals that turned "the passive, vaginal orgasm into the holy grail of female sexuality"; the contemporary religion of clinical medicine seeks to explain and/or treat every possible form of sexual dysfunction.

As Roach explains, "With sex research, unlike, say, engineering or genome research, almost everything a scientist does can appear -- to the uninformed or close-minded outsider -- to be motivated by a perverse fascination with the subject." She notes that "William Masters and Virginia Johnson said of their field in the late 1950s, ' . . . science and scientist continue to be governed by fear -- fear of public opinion, . . . fear of religious intolerance, fear of political pressure, and, above all, fear of bigotry and prejudice -- as much within as without the professional world.' (And then they said, 'Oh, what the hell,' and built a penis-camera.)" Regarding a 1984 study of the female orgasm deemed by its principal investigator to be "ethically acceptable as long as the examiner keeps from being erotically involved with the subject," she points out that "[o]nly in the mutant universe of sexology could a man with his fingers in a woman who is exhibiting 'hyperventilation, . . . rhythmic pelvic movements, vocalizations, and perspiration' not be considered erotically involved."