Bonk: The Curious Coupling of Science and Sex

by Mary Roach

“It is admittedly the most important subject in life,” he wrote. “It is admittedly the thing that causes the most shipwrecks in the happiness of men and women. And yet our scientific information is so meager…. [We should have our questions] answered not by our mothers and grandmothers, not by priests and clergymen in the interest of middle-class mores, nor by general practitioners, not even by Freudians; we…want them answered by scientifically trained students of sex….”

“In direct manipulation of the clitoris there is a narrow margin between stimulation and irritation.”

The stereotypical ideal female—Barbie tall with Barbie big breasts—is the one least likely to respond to a manly hammering.

American manhood would not abide the sexually sophisticated (i.e., demanding) woman, and it fought back hard.

Around ovulation, when a woman is most fertile, they pull material in toward the uterus; during menstruation they expel it. (The reproductive system is smarter than you think, and utterly goal-directed. Not only do sex hormones orchestrate the direction of your uterine contractions, they dilate only the fallopian tube that contains the ovum, so that more semen ends up on that side. They even oversee the quantity and viscosity of your discharge. Around ovulation, cervical mucus becomes more abundant and takes on the stringy consistency of an egg white, providing sperm with a sort of rope ladder into the uterus.)

“By the time a couple gets to an infertility doctor,” said Nachtigall, “their sex life is shot. The intimate, fun, stress-reducing aspect of it is long gone. It’s work.

little-known fact that the last portion of a man’s ejaculate contains a natural spermicide—not intended to kill his own soldiers, obviously, but to annihilate the seed of any who come after him.

Sex is far more than the sum of its moving parts.

vanity as a force more powerful than medicine.

Sex physiologist Roy Levin explained to me that sperm which sit around the factory a week or more start to develop abnormalities: missing heads, extra heads, shriveled heads, tapered and bent heads. All of which render them less effective at head-banging their way into an egg. Levin speculates that that’s why men masturbate so much: It’s an evolutionary strategy. “If I keep tossing myself off, I get fresh sperm being made.” Thereby upping the likelihood of impregnating someone and passing on your genes. Though if conception is the goal, you don’t want the sperm to be too fresh. Daily masturbation would deplete the number of sperm per ejaculate.

To produce an ejaculate with optimum potential for fertilization, Levin recommends a holding time of five days.

A man can have an orgasm—or even multiple orgasms*—without ejaculation, and he can have an orgasm and/or ejaculation without an erection.

exercise has been shown to improve a woman’s ability to get aroused. Which makes sense: Exercise makes the body more efficient at pumping blood.

Young widows, with no sexual outlet and a consequent log jam of womanly seed, were said to be especially prone to hysteria—or “womb fury.”

Audrey Eccles quotes a physician in Obstetrics and Gynaecology in Tudor and Stuart England: “It is most commonly the widowes disease;…when the seed is thus retained it corrupts, and sends up filthy vapours to the brain.”

the evil smell. This line of attack was based on the belief that hysteria was associated with a retracted uterus; foul odors were inhaled to repel the uterus, in the hope that it would retreat back down the body cavity into its rightful position.

For ten-plus centuries, the womb was considered less an organ than an independent creature, able to move about the woman’s body like a badger in its den.

w hy weren’t hysteria sufferers simply told to go home and masturbate twice a week? Because, as you will recall from chapter 6, masturbation has a long history as a shameful, dangerous, and much-discouraged act.

“It’s looking like sex in and of itself can be therapeutic,” says Meston. “It makes you enjoy sex more and want to have sex more. I think the whole use-it-or-lose-it thing definitely applies to women.”

people who have regular orgasms seem to have less stress and enjoy lower rates of heart disease, breast cancer, prostate cancer, and endometriosis. They also appear to live longer.

Women, both gay and straight, will show immediate genital arousal (as measured by a photoplethysmograph) in response to films of sexual activity, regardless of who is engaging in it—male, female, gay, straight, good hair or bad. Men, contrary to stereotype, tend to respond in a limited manner; they are aroused only by footage that fits their sexual orientation and interests.

Women’s genitals may respond indiscriminately to images of sex, but the women themselves will often report being totally unaffected by what they’ve viewed. Based upon how they feel, women are quite picky about pornography.

If no one on Egyptian TV talks about sex, then no one will talk about it in the café or the bedroom or the doctor’s office. Misunderstanding and ignorance will spread.

Your genes want you to get pregnant, and hormones are their magic wand.

This is what primate sex hormones do: “They make individuals perceive other individuals as more attractive than they’d normally perceive them.” Hormones are nature’s three bottles of beer.

In humans, a hormone-based contraceptive levels out the monthly peaks and troughs of one’s natural hormone levels—and, in consequence, those of libido. The Pill supplies a steady daily dose of hormones, enough that your body stops supplying its own unsteady, cyclically fluctuating dose. While the Pill’s estrogen levels are high enough to prevent ovulation, they are lower than a natural mid-cycle peak. Says urologist and sex advice author Jennifer Berman, “The Pill basically puts you into a kind of menopausal state.”

going off the Pill might not restore libido.

The Pill doesn’t make women enjoy sex less, it doesn’t change their responsiveness; it just mutes their drive. A lot of them don’t even notice, and for some, it’s a price worth paying.

“Men’s colognes actually reduced vaginal blood flow.”

In addition to the smell of cologne, the women were turned off by the scent of cherry and of “charcoal barbeque meat.” At the top of the women’s turn-on list was, mysteriously, a mixture of cucumber and Good ’n’ Plenty candy. It was said to increase vaginal blood flow by 13 percent.*

because they “took their time.” They lost themselves—in each other, and in sex. They “tended to move slowly…and to linger at…[each] stage of stimulative response, making each step in tension increment something to be appreciated….” They teased each other “in an obvious effort to prolong the stimulatee’s high levels of sexual excitation.”

The more the researchers and the sexperts and the reporters talked about sex, the easier it became for everyone else to. As communication eases and knowledge grows, inhibitions dissolve and confidence takes root.