These breakthroughs are roughly in chronological order.

Non-procreative sexual behavior is common
In 1886, a psychiatrist named Richard von Krafft-Ebing revolutionized the discipline of sexology by publishing his exhaustively researched tome Psychopathia Sexualis. He'd documented every case he could find of what he called "sexual perversity," including those he'd encountered first-hand among his patients. He defined sexual perversity as pretty much anything that deviated from procreative, heterosexual sex, and put each perversion into its own special category. Though he intended to document perversity, the book had the opposite effect: Many doctors and ordinary people read it and realized that many kinds of "perversity" were so common that they were almost normal. The (relatively) unbiased reporting and taxonomic structure of Krafft-Ebing's book inspired countless other early-twentieth-century researchers, including Sigmund Freud, Magnus Hirschfeld, and Alfred Kinsey. Though published over a century ago, Psychopathia still has the power to shock.

Bisexuality exists
Sigmund Freud, the father of modern psychiatry, is famous for remarking that everyone is bisexual. His idea was remarkable for two reasons. One, it acknowledged that there was a middle position between gay and straight (a relatively rare belief among doctors); and two, it paved the way for a more nuanced understanding of how sexuality exists on a continuum rather than as a binary system. Jumping off from Freud's idea, infamous twentieth century sex researcher Alfred Kinsey created what has come to be known as the Kinsey Scale for sexual orientation. On that scale, 0 is completely heterosexual and 6 is completely homosexual. Kinsey and his colleagues did decades of in-depth research to determine that most people fall somewhere in the middle of the scale. You can see their research in Kinsey's most famous works: Sexual Behavior in the Human Male and Sexual Behavior in the Human Female. All research was based on thousands of anonymous interviews conducted all over the United States.

Medical science can transform men into women, and vice versa
Throughout recorded history, there have been women who lived as men and vice versa. Many cultures even have the idea of a "third sex," often a shamanistic role, which is for people who are neither male nor female. But it wasn't until 1930 that the first sex change operation was performed on a famous Dutch artist named Einar Wegener, who emerged as the woman Lili Elbe. Unfortunately, the operation was crude - it involved implanting ovaries - and she eventually sickened and died (you can read her intriguing memoirs about her transition). The first successful male-to-female sex change operation was performed in Denmark in 1952, and its recipient, Christine Jorgensen, became an international celebrity. Since then, thousands of people have had successful sex reassignment surgeries, moving from female to male and male to female with the assistance of medical science.

Women have orgasms
The female orgasm has been "discovered" several times over the past 130 years. In the nineteenth century, doctors used vibrators to help relieve women of "hysteria," though almost no medical accounts from the time acknowledge that this therapy was basically masturbation. The Victorian Era had given rise to the myth that women didn't have orgasms, and many medical researchers adopted this idea as truth because it was impossible to prove that women were orgasming the way you could prove men were. Though anecdotal reports and throughout the twentieth century indicated women could orgasm the way men could, it wasn't until the experiments of sexologists William Masters and Virginia Johnson in the late 1950s that the female orgasm was finally proven to exist in a scientific manner. Masters and Johnson observed women in the process of orgasming while monitoring everything from blood flow to muscle spasms in their vaginas. (Yes, they actually inserted a dildo-shaped measuring device into the women's vaginas to do their research.) After Masters and Johnson published their research in 1966, several other researchers investigated women's sexual response cycle, quickly discovering the G-spot, female ejaculation, and even looking at orgasming women in MRI machines (you can see a picture of that at the top of this post). Recent research into female orgasm has focused on the neurochemistry of women's brains while they are aroused.

Pregnancy can be prevented with a pill
In 1960, the birth control pill debuted on the market as a contraceptive for women. In the late 50s it had been prescribed to women who suffered extreme menstrual cramps. But in the early 60s the pharmaceutical known as "the Pill" became not just a sexology discovery but shorthand for a sexual revolution that had more to do with culture than science. Freed from cumbersome birth control devices like condoms that depended on male cooperation, women could suddenly have sex without the constant worry that they would become pregnant. Many historians have argued that the Pill helped start a new wave of feminist consciousness. The Pill is an excellent example of how a scientific discovery can have widespread, unintended social consequences.

Homosexuality is not a disease
In 1973, homosexuality was removed from the Diagnostic and Statistical Manual of Mental Disorders (DSM-II). That meant that after decades of debate, the professional psychiatric community would no longer treat homosexuality as a disease. Certainly an unhappy homosexual might be viewed as neurotic, but a happy, well-adjusted gay person would be given a clean bill of health. Many sexologists had been arguing for decades that homosexuality was not a disease, most notably the openly gay psychiatrist Magnus Hirshfeld, who founded the Berlin Institute for Sexology (which was later burned down by the Nazis). But the removal of homosexuality from the DSM made it official: Licensed doctors now agreed that gayness on its own was not an illness.

Many kinds of male impotence can be cured with a pill
In 1998, men got their own version of the Pill. A chemical called sildenafil citrate came to market under the name Viagra. Sildenafil works by relaxing muscle tissues, allowing more blood to flow into the penis. Just as the Pill liberated women from fears of pregnancy, Viagra liberated many men from fears of impotence. While sildenafil didn't set off a cultural revolution, it did represent a major scientific breakthrough - and has helped researchers understand male sexuality better. Viagra and similar drugs like cialis are among the bestselling "lifestyle pharmaceuticals" of all time, raking over 1.5 billion dollars per year.

Orgasms can be caused via direct neural stimulation of the spinal cord
In 1998, the same year Viagra hit the market, Dr. Stuart Meloy made a strange discovery while operating on a woman's spinal cord. He was stimulating her nerves in order to locate the source of her back pain, and when he hit one particular nerve he gave her an instant orgasm. "You should teach my husband to do that," she told him. Meloy went on to patent a spinal implant device, which he hopes to market as a cure for female sexual dysfunction (i.e., an inability to have orgasms). He's in the process of testing the device now, and is actively seeking volunteers - female and male - so that he can perfect the device and bring it to market. Once he's got a version of the device that people can use easily, you can expect a sexual revolution that will make the Pill look like a walk in the park.

Women ovulate more than once per month
In 2003, a researcher named Roger Pierson at the University of Saskatchewan overturned the almost century-old scientific belief that women ovulate once a month. He and his team used simple ultrasound scans on 63 women with normal menstrual cycles, and discovered that a significant number of them ovulated 2 or 3 times per month. Their finding could have a significant impact on how we understand female hormonal cycles and fertility.

Top image, an MRI of a woman during sexual arousal and orgasm, from British Medical Journal.

Psychopathia Sexualis image by drjoanne

Annie Sprinkle reading Alfred Kinsey via The Bohemian

Scientific American's Martin Portner writes:

[Looking at the brains of orgasming men using a PET scanner] scientists also saw heightened activity in brain regions involved in memory-related imagery and in vision itself, perhaps because the volunteers used visual imagery to hasten orgasm. The anterior part of the cerebellum also switched into high gear. The cerebellum has long been labeled the coordinator of motor behaviors but has more recently revealed its role in emotional processing. Thus, the cerebellum could be the seat of the emotional components of orgasm in men, perhaps helping to coordinate those emotions with planned behaviors. The amygdala, the brain's center of vigilance and sometimes fear, showed a decline in activity at ejaculation, a probable sign of decreasing vigilance during sexual performance.

To find out whether orgasm looks similar in the female brain, [neuroscientist Gert] Holstege's team asked the male partners of 12 women to stimulate their partner's clitoris—the site whose excitation most easily leads to orgasm—until she climaxed, again inside a PET scanner. Not surprisingly, the team reported in 2006, clitoral stimulation by itself led to activation in areas of the brain involved in receiving and perceiving sensory signals from that part of the body and in describing a body sensation—for instance, labeling it "sexual."

But when a woman reached orgasm, something unexpected happened: much of her brain went silent. Some of the most muted neurons sat in the left lateral orbitofrontal cortex, which may govern self-control over basic desires such as sex. Decreased activity there, the researchers suggest, might correspond to a release of tension and inhibition. The scientists also saw a dip in excitation in the dorsomedial prefrontal cortex, which has an apparent role in moral reasoning and social judgment—a change that may be tied to a suspension of judgment and reflection.

Brain activity fell in the amygdala, too, suggesting a depression of vigilance similar to that seen in men, who generally showed far less deactivation in their brain during orgasm than their female counterparts did. "Fear and anxiety need to be avoided at all costs if a woman wishes to have an orgasm; we knew that, but now we can see it happening in the depths of the brain," Holstege says. He went so far as to declare at the 2005 meeting of the European Society for Human Reproduction and Development: "At the moment of orgasm, women do not have any emotional feelings."

Check out the whole article on orgasm — it's really interesting.

The Orgasmic Mind [Scientific American]

Here are five orgasm weapons you'll want to stick in your holster.

The orgasm gun from Orgazmo delivers orgasm from a distance via a cheesy "raygun" special effect and can be used to stop bad guys (or give unsuspecting girls a zap). Orgazmo, made by South Park guys Trey Parker and Matt Stone, is a scifi comedy about Mormons, pornography, and this strange device. Can a nice Mormon boy who accidentally becomes a porn star save the world with his orgasm gun? You'll have to rent this flick to find out.

In Larry Niven's "known space" books, he introduces the Tasp — a weapon that delivers intense zaps of pleasure right to your brain. It can be used to incapacitate enemies, who are left writhing on the ground in ecstasy. Or it can be used to slowly train somebody you want to enslave, by giving them pleasurable rewards each time they obey you. Eventually, they'll get addicted to your Tasp and do anything to get another jolt. This is a major plot point in Niven's Ringworld, where the Puppeteer alien has a Tasp installed in one of his heads and uses it to control the other creatures who venture to the Dyson Ring with him.

Ming's ring in the 1980 Flash Gordon movie seems to have some kind of orgasm-inducing, mind-controlling power. As you can see in this video we posted of Ming controlling Dale with the ring, falling under its glowing ray results in writhing and solo dirty dancing moves. Could be good at parties. Or in the throne rooms of Emperors who make speeches about "pathetic Earthlings." Either way.

And although sex ninjas aren't exactly scifi, there is simply no cause to leave out the importance of orgasm weapons in the anime miniseries La Blue Girl. It's the simple tale of rival ninja clans who fight with sex instead of swords. The first person to have an orgasm loses, and often becomes enslaved to the ninja who gives the orgasm. Plus monsters can play too, which makes it even harder to resist those orgasms. After all, a monster can have an infinite number of pleasure-inducing tentacles as you can see here.

There's a really messed-up orgasm electrode in Robin Cook's cheesy medical thriller Brain, about some scurrilous doctors who create a brain-based computer by using the brains of hapless co-eds. In one scene, our hero finds out about the brain experiments, and discovers the secret of using women's brains. The bad guys have their unlucky vicitms half-dissected but still alive, suspended in cerebro-spinal fluid, their brains exposed and their bodies (inexplicably) still attached. (Also, unexplained is why they need only ladies, other than that it's way sexier.) They've implanted electrodes in the women's pleasure centers to get them to perform computer work in their heads. "When we stimulate her, she has the sensation of 100 orgasms," the evil doctor tells our hero. "It must be sensational because she wants it constantly." I love that this doctor knows exactly what 100 orgasms would feel like, as if "orgasm" is a unit of pleasure measurement.

And just to remind you that the reality of these devices is closer than you might think, don't forget that surgeon Stuart Meloy invented a spinal implant several years ago that gives women orgasms. He's patented it, and is in the process of doing tests to turn it into a consumer device.

Stuart Meloy, whose spinal implant causes orgasms in most women, has patented the device and tested it on several women and men a couple of years ago. Now he needs to go through another round of tests as he preps the device for FDA approval to treat "female orgasm dysfuntion," defined simply as an inability to have orgasms. Here's a diagram of how it works. A small box about the size of an Altoids tin is attached to two thin wires that snake under your skin and attach to the nerves in your spine responsible for sexual pleasure. Send electricity through the wires, stimulate the nerves, and watch the hot results.

According to an article last week in the Los Angeles Times:

Women who have used the device say they feel as if their clitoris and vagina are actually being stimulated, to quite realistic effect. ("One woman asked me, 'Would it be considered adultery if I gave the remote control to someone other than my husband?' " Meloy says.)

Some volunteers also report fleeting episodes of clenched foot muscles, Meloy says, probably a result of electrical pulses leaving the spine and stimulating nearby motor nerves. (He wonders if the phenomenon might somehow be related to a common orgasm description: "My toes curled.")

And when the device's pulse intensity is cranked up to maximum, Meloy says, some women find their vaginal and rectal muscles squeezing rhythmically in time with the pulses, even before the orgasmic finale.

And then there's the device above, built in the 1970s to measure and study female orgasm. Its inventor, John Perry, writes:

The combination blood-flow sensor ("photoplethysmograph") and muscle activity sensor ("electromyograph") was first developed to investigate the mechanisms of sexual arousal. Along the lower edge of the sensor barrel a single longitudinal silver EMG electrode is visible. (Two other long silver electrodes are located at 90 and 180 degrees behind the sensor body.) Above the electrode, the dark circle of a photocell aimed at the vaginal wall is visible. To the left of the photocell, the white base of a miniature incandescent lamp is visible. A five-pin DIN plug was molded into the base. An insertion stop, right, prevents the sensor from going too far into the vagina, and a retaining bulb, left, helps to prevent it from falling out during contractions.

Many believe Reich was imprisoned for just his beliefs, but he was actually arrested for claiming that his orgone boxes could do things like cure cancer. That kind of fraud is punishable under the law, but giving the old guy a jail sentence — during which he died — was clearly unnecessary and says more about the times in which Reich lived than the gravity of his crimes. Before he got all into orgones, Reich was famous for writing brilliant psychoanalytic books about why people become fascists (The Mass Psychology of Fascism), and how sexual oppression fits into political oppression (The Sexual Revolution). In the 1970s, orgone boxes and blankets were all the rage among the granola-and-crystals set.

This month, there will be a Reich retrospective at a museum in Vienna and scholars will start getting their knickers in bunches as they send pleading emails to archivists at Harvard, begging to be the first to see the secret papers of the guy who invented orgasm studies.

Scientist's ideas on sex reexamined [AP]