As they seek to document and demystify one of life's great thrills, scientists have run across some real head-scratchers.
How, for example, can they explain the fact that some men and women who are paralyzed and numb below the waist are able to have orgasms?
How to explain the "orgasmic auras" that can descend at the onset of epileptic seizures -- sensations so pleasurable they prompt some patients to refuse antiseizure medication?
And how on Earth to explain the case of the amputee who felt his orgasms centered in that missing foot?
No one -- no sexologist, no neuroscientist -- really knows. For a subject with so many armchair experts, the human orgasm is remarkably mysterious.
But today, a few scientists are making real progress -- in part because they're changing their focus. To uncover the orgasm's secrets, researchers are looking beyond the clitoris, vagina, penis and prostate, to the place behind the scenes where the true magic happens. They're examining the central nervous system: the network of electrical impulses that zip to and fro through the brain and spinal cord.
In an orgasm orchestra, the genitalia may be the instruments, but the central nervous system is the conductor.
Armed with new lab tools and fearless volunteers, scientists are getting first-ever glimpses of how the brain lights up (and, in places, shuts down) when the orgasmic fireworks go off. They're tracing nerves and finding new pathways for pleasure that help explain how people with shattered spinal cords can defy sexual expectations.
A few labs are even tinkering with devices that could put patients directly in touch with their orgasmic abilities by letting them observe their sexual brain patterns and "train" themselves to find the elusive frisson, or (in something akin to the Orgasmatron in Woody Allen's 1973 movie "Sleeper") letting them zap a sweet spot in their spinal cord with toe-curling electrical pulses.
"There's a tremendous amount we don't know about orgasms," says Barry R. Komisaruk, psychology professor at Rutgers University and coauthor of the 2006 book "The Science of Orgasm." "But we're on the verge of getting a lot of very important information and really understanding what to do with it."
It's not just the pleasure principle driving this research, says Julia R. Heiman, director of the Kinsey Institute, a nonprofit organization at Indiana University. Sex is an important part of human relationships, she says, which in turn can affect psychological health. "An awful lot of illness, or treatments for illnesses, interfere with people's orgasms," she says, including multiple sclerosis, cancer, Parkinson's disease, depression and diabetes.
Indeed, if surveys are to be believed, this most delightful of experiences is elusive for many. About 43% of women and 31% of men in the U.S. between ages 18 and 60 meet criteria for sexual dysfunctions, according to a 1999 report on the sexual behavior of more than 3,000 U.S. adults.
Orgasm researchers hope their efforts will help some of these people -- eventually. For now, reports are more likely to include the words "parasympathetic nervous system" than "try this at home tonight."
A difficult subject
It has never been easy to study any aspect of sexuality, let alone one so erotically center-stage as an orgasm. "Almost everybody is interested in orgasms, but it is also very difficult to start this kind of work," especially in the U.S., says Dr. Gert Holstege, a neurologist at University of Groningen in the Netherlands. "The Victorian time is still not over."
So it's not surprising that some of the most impressive discoveries in the field of orgasm science were stumbled upon by accident. For example, Viagra originally was a drug being tested for treatment of high blood pressure and heart disease.
Other touted aids lack formal proof. No doubt most of the nostrums available from pharmacies or the Internet derive their power from the "oh-please-please-make-this-work" power of the placebo effect.
And though sexologists as far back as Alfred Kinsey have tallied people's orgasmic habits in exquisite detail, only now are researchers beginning to understand how it all works.
Orgasms are difficult to define, let alone reverse-engineer. A few blueprints, however, have already been sketched out. First, stimulating the genitals sends electrical impulses along three main paths -- the pelvic, hypogastric and pudendal nerves. Next, these titillating signals enter the spinal cord at the base of the spine and zip up to brain regions that respond to genital sensations.
Then other parts of the brain leap into action. Some send signals back down to the body with certain instructions -- lubricate the vagina, stiffen the penis, pump blood harder, breathe faster.
The intensity builds to a crescendo, and just like a long-awaited sneeze, tension is released in an explosive rush. The heart rate doubles. In women, the uterus contracts rhythmically; in men, sperm-carrying semen is propelled out of the body.