FEMALE ORGASM: THE GREATEST SCIENTIFIC DISCOVERY OF THE 20TH CENTURY?

In which I pose the question: Why are Humans so Fucking Sexy?

[T]he human female is capable of constant sexual arousal. She is physically able to make love every day of her adult life. She can copulate during pregnancy, and she can resume sexual activity shortly after having a child. She can make love whenever she pleases.

This is extraordinary. No females of any other sexually reproducing species make love with such frequency. All other females have a period of heat, or estrus, during which they copulate, and when they are not in heat they do not regularly engage in sex.

-Helen Fisher, The Sex Contract (1982)

Everything in the world is about sex, except sex. Sex is about power.

-Laura Dodsworth, Free Your Mind (2023)

Hey Folks,

So lately, I’ve been on a bit of a sexology kick. Some readers might think that I’m getting a bit sidetracked from serious political philosophy, but I don’t think I am. If you think about it, human politics really does have a hell of a lot to do with sex.

The reason that I’m studying anthropology is because I want to understand human nature so that I can understand what is politically possible and what is not.

My belief is that any political system worth its salt must be aligned with human nature. There’s no point trying to stuff a square peg in a round hole. If a system cannot accommodate human beings behaving like human beings, should it even exist?

And if we want to understand human societies, we must understand that all human cultures are different solutions to the same basic problem - intergenerational survival. And intergenerational survival ultimately comes down to babies and to child-rearing. And where do babies come from? Sex. And what is the primary biological purpose of sex? Reproduction.

Sex is often treated as a topic of marginal concern in politics, but in a very real way, POLITICS IS ABOUT SEX.

As Laura Dodsworth put it:

Everything in the world is really about sex, except sex. Sex is about power.

Actually, I’m beginning to think that sex might be one of the most neglected areas of political philosophy. The question of sex touches upon every aspect of society.

Indeed, if you zoom out far enough and attempt to see human cultures from an trans-generational perspective, individual human beings basically fade into insignificance.

What do you know about your great-great-great-great-great grandparents, for instance? Precious little, I’m guessing. But you know that you would not exist were it not for them. How much does it matter what their individual desires and wishes were? How much can we even know about such things?

My point is this: for the vast majority of people who have ever lived, the most consequential thing they ever did in their lives was reproduce. And chances are that most of them were lead by their sexual desire. Indeed, it seems beyond dispute that human psychology is oriented towards sexual reproduction. It seems reasonable to assume that the purpose of biological life is reproduction.

Yet sex is still seen as something to be feared, to be controlled, to be censured, to be monitored, to be policed… Why? Why is sex so dangerous?

Personally, it makes sense to me to assume the incredible human capacity for pleasure is a big part of what makes us different from other animals.

Simply put, if we are to make a serious study of human nature, we must acknowledge that human sexuality is VERY different from that of other mammals. And if you ask me, the question of sexuality cannot really be separated from other questions regarding human social behaviour.

What we are talking about is a seemingly God-given instinct to seek pleasure. Why do we distrust this instinct so deeply?

Patriarchal religions are notorious for their dread of sex, often imagined as an ever-looming source of woe and havoc, forever threatening to rend society asunder by its corrupting influence… yet sexual desire is also a major force weaving the very social fabric upon which society depends.

Anyway, what you are about to read was written by the Canadian anthropologist Helen Fisher. It is excerpted from a 1982 book called The Sex Contract: The Evolution of Human Behavior, which proposes a theory as to why human females are so fucking sexy.

I think that the whole passage is well worth reading, but I’d like to call your attention specifically to the part which deals with female orgasm.

Personally, I think that it’s pretty incredible that the female orgasm was unknown to science until the 1950s. How crazy is that?

[T]here is no doubt that the human female’s sexual capacity far exceeds that of the apes. Though caged baboons and chimpanzees do copulate occasionally when they are not in heat, and wild chimps and orangutans are known to receive males when they are not in estrus, no female ape enthusiastically makes love every day of her monthly estrous cycle…

A human female’s sexual behavior is not confined to the middle of her monthly cycle. Her genitals do not become engorged at ovulation. No all-pervading odor announces her ripeness. No heightened sex drive compels her to copulate at this time. A woman can make love when she is menstruating and she often encourages copulation throughout pregnancy. Theoretically, she can make love every day and every night, every month and every year of her adult life. In this respect, she is unique among all other female creatures on earth. Women have lost their period of heat…

The result is “silent ovulation.” What a remarkable evolutionary twist this is. Because a woman has no obvious period of heat, a couple that wishes to have a child cannot tell when the woman is ready to conceive. So they must make love regularly. It is almost as if nature had wished human beings to make love daily, for in fact, the human female is particularly designed to do so.

It was not until the 1950s that investigators documented a second extraordinary human female endowment. Not only can she make love with impressive regularity (and has to if she wants a child), but her sex organs generate intense sexual pleasure— even more pleasure than the human male derives from intercourse. For nature has provided the human female with a clitoris, a bundle of nerves designed solely for sex. Even the slightest touch to this supersensitive gland causes sexual arousal. Furthermore, about four or five dense masses of veins and nerves congregate in the muscles of her genitals—and during intercourse these sensitive aggregates sharply distinguish her sexual performance from that of her mate.

As a woman becomes sexually excited, blood pours into the vessels of the genitals and the general pelvic area. The nerve bundles begin to expand. The muscles around the clitoris, vaginal opening, and the anus begin to swell with blood. This pressure is known as the "vaginal ache." Shortly, the spongy sacs that surround the vaginal opening expand to three times their normal size; the inner lips double their size, and the muscles of the entire genital area become engorged with blood.

Then suddenly the distended tissues revolt. They have become overwhelmed with blood and fluid. The pressure is too great, and they contract to expel it. First, the wall of the uterus pulsates, followed quickly by the muscle of the outer third of the vagina, the sphincter of the rectum, and the tissues around the vaginal opening and clitoris. About every four-fifths of a second, a new contraction hurls blood from the pelvic area back into the general system. These rhythmic contractions constitute an orgasm.

For men, orgasm follows the same principle. Generalized physical arousal begins with a thought or touch and causes blood to flow into the penis, making it erect. The tissues of the penis fill with blood until the pressure becomes intense, and then the blood-laden muscles contract.

But here men and women part company—the result of an extraordinary evolutionary change. At orgasm, a man normally feels three or four major contractions followed by a few irregular minor ones, all localized in the genital area. Then sex is over. The blood totally diffuses, the penis goes limp, and the male must start from the beginning to achieve orgasm again. The female pattern is very different. She normally feels five to eight major contractions and then nine to fifteen minor ones, and they diffuse throughout the entire pelvic area. But for her, sex may have just begun. Unlike her mate, her genitals have not expelled all the blood, and if she knows how, she can climax again soon, and again and again if she wants to. In fact, the more orgasms a woman has, the more she can have, and the stronger they become. This phenomenon is known as “satiation-in-insatiation” and it sharply separates the sexual physiology of the human female from that of her male lover. Some of the American women surveyed in The Hite Report confirm this. “One never is enough, two sometimes (rarely) is, but I usually ‘need’ about five once I have the first one,” states one anonymous individual. “After the first orgasm I want to be aroused and have another almost right away. I am capable of several in one session...” wrote another, and a third said, “Each subsequent orgasm is stronger than the preceding.” Though these statements are not typical for American women, many of whom remain unaware of their sexual potential, all human females are physiologically capable of multiple orgasms. It just takes practice. As recently as 1966, not one man or woman among the inhabitants of a rural Irish island had ever heard of female orgasm. But sexual behavior in that region was severely repressed. The Polynesians of Mangaia Island know that female orgasm must be learned, and if one man does not successfully teach a young girl, her education is entrusted to another until she learns to climax several times.

Masters and Johnson first documented “multiple orgasm” in their revolutionary study on female sexuality in 1966, and they recorded another unique physiological attribute of the human female as well. This is the state of “continual orgasm” which they observed in some women. It is actually a series of orgasms that follow each other so rapidly that they are detectable only with machines. The Hite Report uncovered a few American women who experience this. Mangaian women call it “extended orgasm” and enjoy it regularly.

Wow! Hooray for Western science! It only took us five millennia to figure out that female orgasm is a thing.

Ah well, better late than never, I guess.

WHY ARE HUMAN FEMALES SO FUCKING SEXY?

Excerpted from The Sex Contract by Helen Fisher.

American couples make love one to four times a week. This is low by human standards, say Clellan Ford and Frank Beach, the pioneering researchers on human sexual behavior, but when we are not actually making love, we are often preparing for it. Men and women buy clothes to entice mates, cars to impress mates, meals to cajole mates—and advertisers know it. The morning newspaper features a leggy young girl, amid a cluster of suitors, in a dress every woman should own. Automobile ads show a dashing stud driving a car every man should buy. Deodorants, hair tonics, toothpastes, recipes, vitamins, exercise classes, sports clubs, aphrodisiacs, and thousands of other goods and services promise sex today.

We are surrounded by the mating calls of romantic novels. Movies and TV serials daily rehash love’s problems. Country and western, opera, jazz, and rock and roll songs extol love’s ecstasy. Drawings, photographs, and paintings depict love’s pleasure. We laugh at sex jokes, play sex games, and exchange sex stories. We flirt with each other in the office. We parade for each other on the streets and we court each other at restaurants, bars, dance halls, and parties. We employ body stance, gait, gesture, apparel, vocal tone, and eye movements to court mates. And when we snare one, we spend time in bed each week making love.

The Cayapa Indians of western Ecuador are among the world’s most sexually repressed people. The men spend much of their time drinking rum in tiny village shacks that border the Cayapas River. They are shy around women, whom they consider sexually aggressive. Occasionally an adventuresome man will go “night-crawling” to obtain a wife, but most men depend on arranged marriages to find their mates. Many have to be coerced into marriage. The Cayapa see the world as threatening and cannibalistic. They refer to intercourse as the vagina devouring the penis, one of the many sexual fears that pervade daily life among these farmers and hunters. But, oddly enough, even here most men brag of having intercourse as often as twice a week.

Human beings around the world engage in sex regularly, and in many places, people have created rituals to keep sex exciting. The Eskimos traditionally play a game called “douse-the-lights” to exchange sex partners. When the oil lamps are turned on again, gales of laughter and “I knew it was you” jokes add a touch of merriment to the long dark months of the Arctic winter.

On the balmy islands of Ulithi in the western Pacific, the Micronesian fishing people make love every day. Periodically they call a holiday known as pi supuhui, or “a hundred pettings.” On this day or night individuals pair up and go into the woods to relax, picnic, and make love. Married couples cannot go together, and lovers are encouraged to pick a different partner. If the number of participants is unequal, a man or woman is shared. Even the children pick friends and play at hugging and caressing one another.

Among the Turk of Tanzania, most individuals have lovers. Marriage is a business for these planters and herdsmen, and though the women are taught from childhood to obey their husbands, they are not required to love them. Because the Turk feel it is difficult to preserve love with one’s marriage partner, NIbuya, or “romantic love,” is encouraged. Discretion, however, is essential. Lovers meet in the woods, exchange small gifts, and make love regularly. If they are caught, the man usually must pay a fine of sheep or cattle to the offended husband, but often the transgression is ignored.

These people enjoy a celebration of promiscuity at the circumcision rite of their fifteen-year-old boys. During the first day’s activities, couples perform a dance that imitates intercourse. Songs that refer to the penis, vagina, and copulation accompany the dance. The Turk say that if these dances are not “hot,” or full of sexual passion, the celebration will be a failure. That evening they consummate what they have suggested all day.

Central India is the homeland of the Muria, a people who hunted, fished, and tilled the land centuries before the Aryans overran and settled this vast subcontinent. Today each Muria village has a ghotul, or “children’s house,” where the young go to live as soon as they are old enough to carry wood. In the ghotul all activities are shared, including sex. Each night, girls and boys select bed companions and by midnight they are all settled down with their mates. Often a sixteen-year-old girl will cuddle a nine-year-old boy, or vice versa. Sometimes partners only hug and fall asleep, but it is normal for the adolescents to make love. If a couple falls in love, they are requested to sleep with others after three consecutive nights. “This is the way love is preserved,” say the Muria, who believe that lovers should not permit their desires to burn out before marriage.

Along the headwaters of the Amazon, the dense forests and cascading mountain streams provide food and water for the Jivaro Indians. Every man strives to have a large house a good walk from that of his neighbor, with as many wives in it as he can support. Unmarried Jivaro men steal constantly to the homes of potential wives, but married men often sneak about as well. Philandering is so common here that a jealous husband sometimes builds a tampunci, or “adulterer’s trap,” near the family garden. The trap is carefully designed so that when a lover appears along the path a bent tree branch will smack him in the groin. And though there are harsher retributions for adultery, the Jivaro continue to pursue their lovers.

In order to attract mates or paramours, people in every corner of the world have made extraordinary efforts to look sexy. African Bushmen women massage their infant daughters’ genitals so that they will dangle enticingly by teenage years, a mark of good looks to potential husbands. Ulithian women of the western Pacific tattoo the inner lips of their vulvas to enhance their beauty. Men and women have long tattooed their bodies, scarred their faces, filed their teeth, inserted lip-plugs in their mouths, stretched their earlobes, and pierced their ears or noses to achieve sex appeal. And where permanent body disfigurements have not been fashionable, people have donned every imaginable type of temporary decoration for sexual display. Among the most unusual are the two-foot-long penis sheaths made of orange-colored gourds that New Guinea tribesmen wear to decorate their genitals and the high-heeled shoes worn by Western women to accentuate their gait.

We are a species devoted to sex. We talk about it, joke about it, read about it, dress for it, and perform it regularly. We have legends to explain it, punishments to curb it, and rules to organize it. Everywhere there is an accepted way to court a mate, a proper way to marry, a legitimate reason for divorce. Sexual traditions and behaviors saturate our lives.

Why? Because the human female is capable of constant sexual arousal. She is physically able to make love every day of her adult life. She can copulate during pregnancy, and she can resume sexual activity shortly after having a child. She can make love whenever she pleases.

This is extraordinary. No females of any other sexually reproducing species make love with such frequency. All other females have a period of heat, or estrus, during which they copulate, and when they are not in heat they do not regularly engage in sex. For example, most mammals, such as deer, bighorn sheep, and sea lions, have a mating season. At this time the female comes into heat, and her sexual receptivity is broadcast to her suitors by changes in her odor and behavior. These signals touch off the courting ritual. The males of the species compete with each other and the winners mate with the females.

But once a female has conceived, her estrus ends. Her odor wanes, her behavior changes, and until her infant is weaned she will not come into heat again. She will have no physiological period of heat and thus no sex. The males of these mammalian species will have no sex either. They must wait until the females come into heat the following year before they copulate again.

Some members of the primate order also have a mating season. Lemurs, our small, agile, four-footed relatives who once roamed the trees of Africa, now live only on the island of Madagascar.

Among the world’s finest aerialists, they begin their day with airborne leaps from tree to tree in search of fruits and leaves which they devour in the presence of up to sixty comrades. Normally friendly, chatty creatures, they spend hours daily grooming each other’s furry coats and playing with their young. Only in the mating season does this behavior change.

As the females come into heat, the males become aggressive and temperamental. They rush from one female to another, smearing them with fluid from their anal scent glands. Soon social life becomes an orgy of copulating lemurs. But the orgy ends quickly. In a few days the females conceive; their sexual behavior disappears; the chaos stops for another year.

Though our closer relatives, the monkeys and apes, copulate monthly rather than annually, their sexual behavior is also restricted. This was discovered in the 1920s at the Yerkes Regional Primate Research Center in Atlanta, Georgia. Here the Center’s founder, Robert Yerkes, established that all of the female higher primates have monthly menstrual cycles similar to those of the human female. But, unlike the human female, they have a monthly period of heat that lasts about ten days and coincides with ovulation. Thus he concluded that the female higher primates enjoy sexual activity for about one third to one half of every month. That’s a good deal more than lemurs, dogs, or cats, but it does not compare with the sexual abilities of the human female—who can copulate every single day of the month.

Since the 1960s more data have been collected on the sexual behavior of our cousins and it clearly confirms that human females are the sex athletes of the primate world. Characteristic of the monkey pattern is the sex life of the common baboon, and on the plains of Kenya where the squat, low-limbed acacia trees stand in clumps between miles of prairie grass, it is easy to observe.

A young female baboon has been in heat for about six days. To advertise it, the sex skin around her genitals has swollen with blood and blossoms below her tall like a huge pink flower. She has begun to exude a pungent, sexy odor. Days ago, when the swelling and scent began, five young males began to follow her around. To each she had presented her behind as an invitation to copulate, and each had leapt on her back and entered her several times. But now the female is fully ripe, and formidable contenders have arrived to bid for her sexual favors.

Among them is a leader of the troop, a top animal in the social hierarchy. He is a dominant male by virtue of his size and his ability to make friends. He sniffs the female, then suddenly turns on his male companions, rolls back his lips, yawns, and shows his fangs. His body is crouched and ready to lunge as he glares at his potential victims. It is a bluff, but the display works. His competitors back off nervously and the argument is settled. Then he jostles the female to the edge of the troop, periodically posing for his adversaries. Here he will remain to copulate for as long as three days, stopping only to eat, sleep, or defend his prize. Between mountings the couple relaxes. She untangles his mane with her fingers, he licks her face and fur, and they nuzzle in friendship and camaraderie.

As her swelling declines, their “consort” relationship breaks up, and both male and female re-join the troop’s daily life. If another female comes into heat and he can intimidate competitors, the male may have sex again soon. But his recent partner will not. During their time together she has become pregnant. She will not have another estrus while carrying the embryo, nor until after weaning her infant. So she will have no suitors, or sex, for at least two years. Even then her love life will be brief. For a third of every month she will resume estrus, but soon she will be pregnant again and once more her estrus will disappear for years.

Like baboons, female chimpanzees also have a period of heat each month. And though it restricts their sex lives, they have learned to make the most of it. The most blatant example is the sexual behavior of a now-famous chimp named Flo.

Flo, who recently died of old age, was for years a member of a chimpanzee group that roamed a fifteen-mile home range in the forests and woodlands of the Gombe Stream Reserve, Tanzania. She was the pride of anthropologist Jane Goodall, who began a pioneering study of these remarkable animals in 1960. Mother of four and senior madame of the group, Flo eagerly serviced most of the males when she was in heat. As her bottom swelled and reddened, she presented it to the first male she saw and permitted him to pat, poke, and sniff her. Then she crouched as he mounted her from behind. When he was satisfied, she greeted another in the lengthening line of suitors who patiently waited their turn. Hours later she would relax in the forest underbrush with her most recent lover and permit him to groom her ruffled, sweaty hair.

During Flo’s estrus she would copulate indiscriminately with any male who wanted her. Among them she had friends, allies with whom she traveled in search of food and comrades near whom she nested at night. But she played no favorites. Only Flo’s sons got no opportunity to make love to their mother.

Although Fagen, the oldest, was a young, powerful, and popular member of the group, he behaved like a child in her company and made no overtures for sex. Nor did she invite sex with him. Instead, she felt compelled to mother him.

Flo’s daughter, Fifi, watched. As a child, Fifi was annoyed when her mother began her amorous escapades. She felt ignored and often tried to wrestle the suitors from Flo’s back. But as Fifi grew older she began to practice her mother’s ways, tipping her buttocks to passing males in hopes of gaining their attention. Today Fifi has become what Jane Goodall calls a “chimpanzee nymphomaniac.” Yet even Fifi makes love only when she is in heat. For after a chimpanzee has ovulated, the pinkness of her estrus begins to disappear. Her swollen bottom shrivels and her odor becomes normal once again. Now her frenzied sex life is temporarily over. Though she may flaunt her genitals occasionally and even be mounted at times, until she comes into heat next month the males will be lining up for others. If she has become pregnant during her estrus, she will not ovulate again. During the first few months of pregnancy she will occasionally have a sexual swelling, but she will have no menstrual cycle, no regular estrus, no regular sex. And after she gives birth, a female chimpanzee will not resume her sex cycle until her child is weaned. For young mothers this is about two years. For fully mature females, such as Flo, the period of abstinence can be almost five years long. She eventually will resume her estrous cycle, but it will last only until she becomes pregnant again. So the amount of time a female chimp actually is willing and able to spend at sex is small—about 1 percent of her life.

Is the formidable-looking gorilla any sexier? George Schaller trekked through the dense tropical forests of Uganda and Zaire in 1959 to find out. Gorillas travel in small groups averaging about sixteen individuals. Each group has one dominant adult male who, by virtue of his silvery coat (which advertises his maturity) and huge size, leads a harem of females and defends their young. All year round they follow him, eating, sleeping, chattering, and grooming one another in his company. Younger, subordinate, black-backed males remain with their natal group if they have a possibility of running it someday. If not, they disappear to steal females from other groups and form their own harems.

Day after day Schaller followed their trails of discarded food, trampled vegetation, and dung, until finally, a group of gorillas became used to him. And one morning Schaller saw some sex. A young female displayed her genitals to a subordinate black-backed male and he mounted her from behind. Then she mounted him and began thrusting until he turned and pulled her onto his lap. Schaller saw three rapid copulations within an hour. The commotion occurred within yards of the dominant silverback, who appeared totally unconcerned by the ruckus. Schaller observed a similar sexual performance only one other time during his year of observation among the gorillas.

Because Schaller and other researchers found it difficult to find sexy gorillas in the wild, Ronald Nadler recently decided to explore their sex lives at the Yerkes Regional Primate Research Center. Every day he paired one of four female gorillas with one of nine males and recorded their behavior. The males never approached the females, and females who were not in heat rarely approached the males. But when a female was in heat—a brief period of about four days—she actually tracked the male and sometimes coerced him into copulating several times. One female began her sexual overture with a soft, high, fluttering speech as she backed her intended mate into the corner of the cage. When she had him pinned, she rubbed him rhythmically with her genitals until his penis grew hard and he penetrated her. Another approached her mate, grabbed him by the hair, rolled down onto her back, and pulled the male down on top of her to copulate face-to-face. In all cases, the female was the aggressor.

Perhaps this lack of male initiative is because gorillas do not produce the obvious swollen genitals that serve to announce the advent of estrus among baboons and chimps. Whatever the reason, life seems to be a perpetual Sadie Hawkins Day for the caged gorilla—but only during those few days when the female is in heat.

Only our red-haired cousins, the orangutans, seem able to copulate all month long. These elusive creatures live in the forests of Borneo and Sumatra, where both males and females spend most of their lives alone. The orangutans split off from our ancestry about the same time the gorillas and chimpanzees did, and all three genera score in the same range on intelligence tests. But because the orangutans do not live in Africa, the long-thought cradle of mankind, and because they are semi-solitary creatures, investigators found them uninteresting. So until recently nothing has been known of their sex lives.

Nadler caged four orang couples at the Yerkes Center and watched. Every day he saw some sex. Each encounter began with a series of roars by the male as the female entered his cage. Then the male chased the unwilling and often frantic female around the cage until he wrestled her onto her back. When she succumbed, he spread her legs, held her thighs with his feet, and squatted over her to copulate face-to-face. During intercourse he often adjusted her position by turning her onto her stomach or side. Variations included sex while hanging from the ceiling of the cage, where she would suspend in hopes of eluding him. Neither partner grimaced nor expressed any pleasure vocally, as most primates do when they get sexually excited. In fact, the female often appeared bored by the whole procedure, looking around the cage, casually picking at her fur, and occasionally grabbing a bite of food—even during the height of the lovemaking.

When sex was over, the orangs retired to separate areas of the cage to clean up, and then the male often fell asleep. Occasionally a female tugged at her mate, slapped him, or pulled his hair to get his attention, but no male returned the gesture. The female was either ignored or rebuffed as he dozed off. Among orangs it is hardly a woman’s world.

Although the female orangutan has no monthly sexual swelling, Nadler noticed that females were eager for sex only in the middle of their cycle. At this time, the females spent more time grooming themselves. One female even bounced her genitals on a male’s head as an invitation to make love. Some masturbated with a wire or by rubbing their genitals against the cage. The males also became more ardent lovers in the middle of the female’s cycle, frequently demanding multiple copulations. From all this, Nadler concluded that a trace of estrus still existed in the orangutan female, even though she can be coerced into making love all month long. Recently, researchers living in the jungles of Borneo confirmed Nadler’s conclusions. Females do copulate all month long. But generally, they must be coerced, and sometimes they are raped.

From this evidence, there is no doubt that the human female’s sexual capacity far exceeds that of the apes. Though caged baboons and chimpanzees do copulate occasionally when they are not in heat, and wild chimps and orangutans are known to receive males when they are not in estrus, no female ape enthusiastically makes love every day of her monthly estrous cycle. Only rarely has a female ape been seen to accept a male while menstruating. No female ape initiates copulation as her fetus comes to term. And no female ape resumes her menstrual cycle to copulate on a regular basis before her child is weaned. Only the human female is different.

A human female’s sexual behavior is not confined to the middle of her monthly cycle. Her genitals do not become engorged at ovulation. No all-pervading odor announces her ripeness. No heightened sex drive compels her to copulate at this time. A woman can make love when she is menstruating and she often encourages copulation throughout pregnancy. Theoretically, she can make love every day and every night, every month and every year of her adult life. In this respect, she is unique among all other female creatures on earth. Women have lost their period of heat.

Actually, traces of estrus remain—and a few clever women use them for birth control. Shortly before ovulation, a slippery, smooth, colorless mucus appears along the walls and exterior of the previously dry vagina. Then after ovulation, it suddenly becomes cloudy and sticky for a few days until it disappears altogether for another month.

Also at ovulation, the cervix, the muscular tissue that separates the vagina from the uterus, becomes soft and slippery. It opens and rises (perhaps to make more room for the penis) and then immediately after ovulation it lowers, hardens, dries, and the opening closes for another month. Some women feel cramping during ovulation at the moment the egg pops from the ovary to begin its descent into the uterus. A few women bleed slightly at this time. Others find their hair is unusually oily, their breasts are sensitive, or they have more energy than usual. The female’s body temperature rises almost a full degree at ovulation and remains normal or above until the next menstruation. And she becomes more electrically charged as well.

So if a woman inspects the mucus in her vagina or her cervix daily, if she notes the cramps of ovulation, or faithfully takes her temperature every morning before rising, she will know when she is ovulating. Otherwise, she will not. No period of heat—with its concomitant scent, swelling, and behavior—announces fertility.

The result is “silent ovulation.” What a remarkable evolutionary twist this is. Because a woman has no obvious period of heat, a couple that wishes to have a child cannot tell when the woman is ready to conceive. So they must make love regularly. It is almost as if nature had wished human beings to make love daily, for in fact, the human female is particularly designed to do so.

It was not until the 1950s that investigators documented a second extraordinary human female endowment. Not only can she make love with impressive regularity (and has to if she wants a child), but her sex organs generate intense sexual pleasure— even more pleasure than the human male derives from intercourse. For nature has provided the human female with a clitoris, a bundle of nerves designed solely for sex. Even the slightest touch to this supersensitive gland causes sexual arousal. Furthermore, about four or five dense masses of veins and nerves congregate in the muscles of her genitals—and during intercourse these sensitive aggregates sharply distinguish her sexual performance from that of her mate.

As a woman becomes sexually excited, blood pours into the vessels of the genitals and the general pelvic area. The nerve bundles begin to expand. The muscles around the clitoris, vaginal opening, and the anus begin to swell with blood. This pressure is known as the "vaginal ache." Shortly, the spongy sacs that surround the vaginal opening expand to three times their normal size; the inner lips double their size, and the muscles of the entire genital area become engorged with blood.

Then suddenly the distended tissues revolt. They have become overwhelmed with blood and fluid. The pressure is too great, and they contract to expel it. First, the wall of the uterus pulsates, followed quickly by the muscle of the outer third of the vagina, the sphincter of the rectum, and the tissues around the vaginal opening and clitoris. About every four-fifths of a second, a new contraction hurls blood from the pelvic area back into the general system. These rhythmic contractions constitute an orgasm.

For men, orgasm follows the same principle. Generalized physical arousal begins with a thought or touch and causes blood to flow into the penis, making it erect. The tissues of the penis fill with blood until the pressure becomes intense, and then the blood-laden muscles contract.

But here men and women part company—the result of an extraordinary evolutionary change. At orgasm, a man normally feels three or four major contractions followed by a few irregular minor ones, all localized in the genital area. Then sex is over. The blood totally diffuses, the penis goes limp, and the male must start from the beginning to achieve orgasm again. The female pattern is very different. She normally feels five to eight major contractions and then nine to fifteen minor ones, and they diffuse throughout the entire pelvic area. But for her, sex may have just begun. Unlike her mate, her genitals have not expelled all the blood, and if she knows how, she can climax again soon, and again and again if she wants to. In fact, the more orgasms a woman has, the more she can have, and the stronger they become. This phenomenon is known as “satiation-in-insatiation” and it sharply separates the sexual physiology of the human female from that of her male lover. Some of the American women surveyed in The Hite Report confirm this. “One never is enough, two sometimes (rarely) is, but I usually ‘need’ about five once I have the first one,” states one anonymous individual. “After the first orgasm I want to be aroused and have another almost right away. I am capable of several in one session...” wrote another, and a third said, “Each subsequent orgasm is stronger than the preceding.” Though these statements are not typical for American women, many of whom remain unaware of their sexual potential, all human females are physiologically capable of multiple orgasms. It just takes practice. As recently as 1966, not one man or woman among the inhabitants of a rural Irish island had ever heard of female orgasm. But sexual behavior in that region was severely repressed. The Polynesians of Mangaia Island know that female orgasm must be learned, and if one man does not successfully teach a young girl, her education is entrusted to another until she learns to climax several times.

Masters and Johnson first documented “multiple orgasm” in their revolutionary study on female sexuality in 1966, and they recorded another unique physiological attribute of the human female as well. This is the state of “continual orgasm” which they observed in some women. It is actually a series of orgasms that follow each other so rapidly that they are detectable only with machines. The Hite Report uncovered a few American women who experience this. Mangaian women call it “extended orgasm” and enjoy it regularly.

Almost all books on sex say that female orgasm is a uniquely human pleasure. Don’t believe it. All of the female higher primates have a clitoris and some seem capable of intense sexual excitement. In a recent study, three rhesus monkeys were strapped to a table while a plastic penis was used to stimulate their genitals. Two of the three responded with vaginal spasms. In another lab test with stump-tailed monkeys, 143 sexual escapades were observed, and intense body spasms and rectal contractions occurred in many females during the peak of intercourse. Flo, the notoriously sexy chimpanzee of the Gombe Stream Reserve, often copulated until she was torn and bleeding, a symptom of satiation-in-insatiation. But these primates are restricted by their monthly cycle. Unlike the human female, they have orgasms (when they do) only while they are in heat.

Human females can have orgasms any time they want to. In fact, in the 1950s Kinsey reported that 90 percent of American women had their best sex at the end of their monthly cycle. This is a bit odd. It is not a time when a woman can get pregnant. Yet at this time blood pools naturally in the pelvic area—a phenomenon known as the “premenstrual tension syndrome”—and creates pressure in the female genitals that heightens the intensity of orgasm. It seems that nature has even made menstruation sexy for the human female.

Pregnancy and motherhood bring sexual rewards too. During pregnancy, new capillaries are built to feed the expanding pelvic area, and fluid congregates in the genitals—heightening the force of orgasm. Childbirth provides the genitals with added circulation too. So for a mother, the contractions of orgasm are more intense than they are for a childless woman. And sex gets better with each new child. Physiologically, it is peculiar that human females experience orgasm at all. Only the male of the species needs contractions to pump his sperm into the vagina of the woman. Her egg drops naturally from the ovary into the uterus once a month at ovulation. She doesn’t need orgasm to procreate. In fact, orgasm may be detrimental to conception because the pulsations move downward starting from the uterus and tend to push semen out rather than up the vaginal canal. Despite this, orgasm can be intense and continual in the human female. Indeed, nature has outdone herself to make sex constantly gratifying for women.

Another female curiosity is the sexual world of the new mother. Almost immediately after the birth of her child, the human female is back at sex again—and she can conceive too. In Western societies, where the bottle has replaced the teat for milk, mothers resume their menstrual cycle and begin to ovulate about six weeks after delivering a child. In other societies, such as that of the Rung Bushmen of the Kalahari Desert in Africa, nursing seems to suppress ovulation for about ten months. But unlike any other primates, human females can make love and reproduce years before their young are weaned. It seems counterproductive that the human female is able to copulate within weeks or months after delivering a child. The human infant is totally helpless. Yet soon after parturition, its mother’s menstrual cycle will return; her sexual desire will reappear; she will begin to copulate again. And what if she conceives another child? Then she will have two helpless infants to support through the most vulnerable period of their lives.

This can create difficult social problems. Among the Yanomamo, belligerent warriors who live along the Orinoco River in Venezuela, a woman who bears a second child too soon after the first must often kill the newborn. When anthropologist Napoleon Chagnon lived among these people, Bahimi, the wife of a village leader, was forced to kill her newborn son so that Ariwari, her two-year-old, could drink her milk. Tearfully, she reported to Chagnon that since she lacked enough milk to feed both youngsters, the infant had to be sacrificed to ensure the survival of her older son.

The Yanomamo practice a crude form of birth control. A pregnant woman simply requests a friend to jump on her stomach until the fetus is aborted. In other parts of the world, women drink potions or carry amulets to prevent unwanted births. In many places, cultural taboos dictate sexual abstinence after a child is born. Some Polynesian mothers insert a hibiscus root into the uterus to avoid pregnancy, and women in industrial nations use plastic intrauterine devices, birth control pills, diaphragms, and abortion to avoid having a second child immediately after delivering one. Close births are a uniquely human problem, the result of another evolutionary twist designed to enable the human female to engage in sex regularly.

As nature’s final straw, she has endowed the human female with a few superficial sexual qualities of an unusual nature. Adult women around the world have breasts. These develop at puberty, like the fatty deposits on their buttocks, and both attributes universally distinguish them from men. At puberty, human females also retain the high voice and hairless face and body they had as children.

Human breasts have no physiological function. They are subcutaneous deposits of fat around the teats and mammary glands that can be cumbersome to the bearer. They play no role in nursing. In fact, they can even smother the child. Fatty buttocks don’t seem to have much use either. They do store fat, and among African Bushmen, where hunger may have been a problem, women have the biggest rear ends in the world. (These women’s buttocks are, in fact, so large that a small child can ride on his mother’s back, standing with his feet on her buttocks and his arms around her neck.) But fleshy buttocks appear on all women, from the cave-dwelling Tasaday of the Philippines to the disco dancers of Los Angeles, even though for most of these women malnutrition is no problem. Big breasts and buttocks appear superfluous, as does the female’s high voice and hairless chin and chest.

Another superficially unnecessary female attribute is her ability to copulate face-to-face. Frontal copulation is not seen among the monkeys. It is unusual among chimpanzees, common among gorillas and orangutans, and the norm for human beings. In every human society studied, couples make love in this position regularly. Why? Because they can. The human female has evolved a vagina which is rotated forward—so for her it is comfortable to make love face-to-face. Furthermore, it can be intensely gratifying, because in this position her mate’s pelvic bone rubs against her clitoris.

Irenaus Eibl-Eibesfeldt, a behaviorist at the Max Planck Institute for Behavioral Physiology in West Germany, has uncovered what he thinks is another innate sexual attribute—flirting. Recently he traveled around the world with a special camera which secretly takes pictures from the side. In this way, he captured and recorded the unstaged flirtations of young women from Samoa, Papua, France, Japan, Africa, and South America. All flirted in exactly the same manner. First, the woman smiled at her admirer and lifted her eyebrows in a swift, jerky movement. This briefly displayed more of her eyes until she turned her head sideways, looked away, and dropped her eyelids. Is flirting an innate sexual behavior pattern? If so, it is no different from the loss of estrus or the development of breasts—all unique human female sex gear.

So this is our legacy. Unlike all other female organisms, the human female has lost her period of heat. Thus she can make love every day of every month of every year. She can copulate while menstruating, pregnant, and shortly after she delivers a child. She can achieve multiple and continual orgasms, and the more she has, the more she can have and the stronger they become. They even increase with menstruation, pregnancy, and childbirth. She has breasts, protruding buttocks, a smooth body, a hairless chin, a high voice, and a forward-rotated vagina. Finally, she is a born flirt. All encourage sex.

Why has nature been so generous to women—and to men? The answer lies deep in the misty past—when our ancestors became sex athletes in order to survive.