The shaft is actually composed of the corpora cavernosa, twin tube-like compartments that form most of the penis shaft; underneath them, along the center of the shaft’s bottom runs the corpus spongiosum, which contains the urethra and at the end of the penis becomes the glans. The small opening or slit at the tip of the glans is a multipurpose exit for both semen and urine. In men, but not in women, the urethra has a role in the reproductive system, carrying semen and the sperm within it on the final leg of their journey when a man ejaculates. All three penile tubes, the two corpora cavernosa and the corpus spongiosum, are made of erectile tissue—tissue that expands when stimulated as blood rushes in and fills its spongy cavities.
That’s exactly what an erection is—a rush of blood into the penis. When a man is sexually aroused, nitric oxide (NO) is released in the genital area. Nitric oxide is a vasodilator—it can make blood vessels dilate wider. This produces a flood of blood into the penis, almost all of it into the twin tubes of the corpora cavernosa. These swell and harden, causing the penis to expand in length and diameter and become erect, enabling the penis to penetrate the vagina in intercourse. The corpus spongiosum has a different role to play. It also swells, but to a much lesser degree. It remains softer and pliant in order to keep the urethra open. Otherwise, there would be no way for sperm to get out of the penis. All that work to get a penis inside a vagina would be for naught, reproductively speaking.
So that’s what an erection in men is all about—blood and spongy tissue. The one thing that it isn’t is bone. “Boner” is a big-time misnomer—at least, that’s what you’d think if you only studied humans. Actually, most mammals do have a penis bone, called a baculum (and a clitoris bone too). Humans are one of just a few exceptions to the rule; even our closest genetic cousins, chimpanzees, have a penis bone, as do all other primates, cats, dogs, bears, and whales. In Alaska, the baculums of sea mammals, like those of seals and walruses, are called oosiks. They are polished and used as knife handles and even sold as souvenirs.
But men definitely shouldn’t fret about their boneless member—it helps make sex fun. When it comes to mating, animals have a need for speed because that’s a time when they’re vulnerable to predators. The baculum makes mating fast: since the penis doesn’t need to form an erection to penetrate, there’s no need for foreplay, just a quick in and out in thirty to sixty seconds, sometimes even less. Humans’ fluid-propelled system takes some time to work up and some stimulation to keep it going; this also allows sex to last longer (but not always). So add the hydraulic penis to the big brain and opposable thumb on the list of things that separate us from most of the animal pack.
EVEN THOUGH HUMAN penises have no bones, they do have something in common with bones, and it’s not a happy coincidence. Like bones, human penises can break.
That’s right, you can break your penis.
Medically it’s called a “penile fracture,” and thankfully it’s not that common. Here’s how it can happen.
The corpora cavernosa are surrounded by a thick layer of tissue called the tunica albuginea, which provides the resistance against which the swelling blood within the corpus cavernosum expands during an erection. In cases where an erect penis is bent at an angle that the tissue cannot sustain, the tunica albuginea can rupture. What is the most common way that happens? Someone about to engage in passionate intercourse misses his target and slams into the pubic bone of his partner. And when that happens, he knows it. There can be a loud cracking or popping sound, and serious pain. The penis will usually bruise rapidly as blood floods and leaks into the surrounding tissue. I will never forget the first time I came across a penile fracture. The patient had tried to masturbate with a metal vacuum cleaner tube—while it was hooked up and turned on.
In particularly bad breaks, the urethra can even be damaged; this can permanently impair the ability to urinate and to inseminate through intercourse. Usually, however, there is no impact on fertility, because a penis break doesn’t involve the testicles, which is where sperm are stored; it’s the possibility of natural insemination that’s at risk. One of the more common ways for a penile fracture to occur is in heterosexual intercourse, during the down stroke with a semierect penis, with the woman on top.
A seriously broken penis can be repaired through surgery, but it needs to be done quickly. If it ever happens to you, put your penis on ice (a bag of frozen vegetables will do) and get yourself to the emergency room and ask for a good urologist pronto.
In humans, a broken penis is rare, and in the unlucky circumstance that it occurs, it can be fixed. Male honeybees aren’t so lucky.
Early in college, before turning my attention to the study of human disease and sexuality, I became interested in insect sexuality while researching how honeybees deal with microbial and parasitic infections. As a result, I came away with a new understanding of just how interrelated processes throughout nature are. In the case of male honeybees, not only do their penises break off when they mate with a queen bee; they die within hours of their first and only sexual encounter. I’ve always thought that honeybee society exemplified the idea of the disposable male, a society run entirely by females whose male members’ only purpose is sexual reproduction. Here is the short, sweet tale of the sex life of a honeybee.
Depending on the time of year, beehives can have a few hundred male drones and thousands of female workers, but only one queen. Only the queen can lay fertilized eggs. Unfertilized eggs become more male drones; fertilized eggs become more female workers. And workers don’t have it much better than drones: they don’t mate at all; they can only sting once; and when they sting, they die.
The queen is a bee of a very different bonnet. She can sting over and over again and she can mate many times with different males. When the mood strikes a young queen, possibly soon after she is born, she’ll leave the hive for a maiden voyage on a spectacular search for sex. (Queens, by the way, are created when workers feed larvae a special diet consisting of a nutritious secretion called royal jelly. All larvae are fed some royal jelly, but incipient queens are fed only royal jelly.)
As she flies, she casts a trail of pheromones that can bring thousands of males congregating around her, looking for their chance to inseminate her. Mating is in midair; it’s quick, but comes with a bang (you can often even hear an audible “pop” as the male drone flips out his penis) for the bee in question. In order for a male to get lucky, he must be near the queen when she opens her sting chamber, making herself available for mating. This may sound rather straightforward, but stop and think for a moment about the spatial orientation, mechanics, physiology, and physics required to bring a queen and male bee together in midair and midflight at heights estimated at more than one hundred feet. The lucky male that manages the acrobatic feat of finding a queen midair rapidly mounts her, pops out his endophallus (the technical name for his penis), and inserts it into her sting chamber (a sort of multipurpose vagina).
Dr. Mark Winston, a biologist who has worked with insects for more than twenty-five years, writes in The Biology of the Honey Bee: “Mounting and copulation are rapid and spectacular, with the drones literally exploding their semen into the genital orifice of the queen…. The explosive and sometimes audible ejaculation ruptures the everted [extended] endophallus and propels the semen through the queen’s sting chamber and into her oviduct.”
When the male inserts his endophallus into the queen, he then flips backward, becoming paralyzed in the process. The force of ejaculation separates the male from the queen and he falls to the ground, where he will die within hours, usually from dehydration. But semen isn’t all he’s left behind. He’s left his penis too. And the next male in line to reproduce with the queen in flight will grab hold of it and throw it away, making way for his own penis and eventual demise.
Some researchers believe the honeybee’s detachable penis helps to prevent backflow of semen. But that’s probably not its only function. It may also serve as a “mating sign,” evidence to workers back in the
hive that the queen has in fact mated.
And what happens to the last endophallus? The queen brings it home where it serves to indicate a successful trip. But then, according to Dr. Winston: “A queen returning from a successful mating flight generally is carrying the mating sign of the last drone to mate her, and the workers which greet her lick the sign with their tongues and eventually remove it with their mandibles.”
A successful queen returns to her hive with up to 6 million sperm, and she can store them for up to four or five years as she produces hundreds of thousands of offspring to keep her hive buzzing busily along. Now, human males don’t leave their penises behind, of course, and the act of intercourse isn’t a death sentence, but, like male honeybees, some men expend much energy (think dinner and flowers) to leave millions of male germ cells (sperm) in the hope that just one of them will successfully combine with a single female germ cell (egg). When it comes to the relative value of male and female cells in some reproductive economies, males are plentiful and expendable, but females are rare and precious.
HUMAN PENISES CAN break, but unlike bee penises, they don’t break off. There is, however, one small piece of the penis that millions of men—around one-sixth of the world’s population—have had removed, their foreskin. Circumcision is the name for the surgical procedure that cuts it away, usually soon after birth. In most cases, the foreskin is removed for religious or cultural reasons; for Jews and Muslims, especially, it’s considered a sacred obligation. It’s thought that the ancient Egyptians also practiced circumcision. But in a few Western countries, notably the United States, circumcision was routinely performed upon many newborn males in hospitals unless the parents directed otherwise, either because they didn’t want their baby circumcised at all or because they were planning on performing a ritual circumcision in a religious ceremony.
Today, there is more and more controversy over circumcision—especially in light of growing understanding about female circumcision, or female genital mutilation, which in some societies involves much more than the removal of an equivalent piece of skin.
Essentially, the foreskin is a thin layer of specialized tissue that covers and protects the head of the penis; it retracts when the penis is erect, or it can be pulled back manually when the penis is flaccid. Like vulvas, penises, and breasts, as well as eyes, noses, fingers, and just about every other anatomical feature, foreskins vary greatly, especially in color and size.
In some men, the tissue covers part of the glans, sort of like a turtleneck pulled up to the ears. In others, it hides the head of the penis completely, hanging over the tip just as the hood of an oversized sweatshirt might droop over the face.
The underside (interior when unerect) of the foreskin secretes a moist substance, part of which can form the cottage cheese–like substance known as smegma which makes it easy for the foreskin to glide over the head of the penis. This hot, wet environment can be an ideal place for bacteria and other microbes to creep in and make it their home, unless men are careful to keep the area clean. In some environments, such as the desert, keeping things clean is more challenging. It’s easy to imagine grains of sand slipping into the tight space between the foreskin and glans, possibly making for an irritating environment.
Which is why some researchers believe the institutionalized traditions of circumcision grew up in the original desert homes of Judaism and Islam. “Circumcision has a long history in ancient societies of the Middle East,” writes Dr. John Hutson, “and is likely to have arisen as an early public health measure for preventing recurrent balanitis [inflammation of the head of the penis], caused by sand accumulating under the foreskin.”
If the foreskin is such a breeding ground for infection—to the point where it impedes reproduction—why do we have them in the first place? Anything that can get in the way and completely prevent reproduction should be ejected from the gene pool unless the benefits it confers outweigh its risks.
There are a range of theories about the utility and benefit of foreskins. Perhaps the moisture it secretes facilitates intercourse—and thus, reproduction—by making penetration easier. Another theory suggests that the foreskin acted like a protective cover for the penises of our very early, very naked, ancestors as they roamed through the bush searching for food or shelter. Yet another theory holds that, like the clitoris, the foreskin has a more pleasurable purpose—to make sex feel good, lubricating men’s partners, encouraging the intercourse that, until modern science has enabled fertilization in the doctor’s office, has been a prerequisite for reproduction.
In a 1999 study, 139 women filled out questionnaires about their sexual satisfaction. In that study, discomfort during intercourse was eleven times more likely with a circumcised partner than an uncircumcised partner. The report’s authors hypothesize that this is because, during intercourse, an uncircumcised penis “does not slide, but rather glides on its own ‘bedding’ of movable skin…with minimal friction or loss of secretions.” This provides some support for the foreskin pleasure principle, although it’s not proof positive by any means.
In Victorian England, circumcision was popularized by its advocates who argued that not only did it help to keep the shameful allure of sexual desire in check, it somehow curbed the sin of masturbation itself, or so they believed.
Cultural unease with sexuality is a driving force behind many of these traditions. And nowhere is that more the case than the appalling practices of female circumcision, a form of genital mutilation, which is still all too present today. According to UNICEF, around 3 million girls are subjected to this brutal practice every year.
There are three basic types of female genital mutilation, and they are performed without any type of anesthesia in almost all cases. In the least extreme case, least being quite relative, the clitoral hood (which is somewhat analogous to the male foreskin) and, sometimes, part of the clitoris is removed. In a more radical procedure, the entire clitoris is removed, along with the inner labia. And in the most extreme form of female circumcision, the entire clitoris and the inner labia are removed and the opening of the vagina is sewn closed or narrowed considerably to prevent intercourse until marriage.
These practices result in a host of dangerous complications. Women who have been subjected to the most extreme type of genital mutilation are 70 percent more likely to hemorrhage after giving birth. These same women are also as much as 55 percent more likely to have a stillborn baby, a result, it is thought, of the increased risk of infection associated with genital mutilation. And, of course, women whose clitorises are excised lose much of their ability to enjoy sexual pleasure and fulfillment.
But how can the cultural tradition of female circumcision be condemned if the cultural tradition of male circumcision is somewhat tolerated, even accepted? There are three critical differences between male and female circumcision. First, while there are potential complications from the procedure of circumcision, as there are with all surgical procedures, they are very rare. (This is not to say they aren’t serious: infections and penile amputations can and do occur.) Second, while male circumcision is generally performed on an infant in a sterile environment, female circumcision often happens at a later age and in unsanitary conditions. Third, unlike most forms of female circumcision, male circumcision leaves the great majority of pleasure-producing tissue intact.
Or does it? It’s hard to know. Ask most circumcised men if their sex life has been hampered by their circumcision and they’re likely to look at you like they have no idea what you’re talking about. Researchers from Johns Hopkins University recently completed a study of 4,456 Ugandan men; half were circumcised as part of the study, and the other half were left uncircumcised. The study showed virtually no distinction between the two groups in terms of pleasure and satisfaction after two years. 98.4 percent of the circumcised men said they were sexually satisfied, as did 99.9 percent of the uncircumcised men. And 99.4 percent of the circumcised men reported no pain during intercourse, compared to a statistically indistingui
shable 98.8 percent of the uncircumcised men.
Of course, the jury’s still out. The only people who can truly compare circumcised sex to uncircumcised sex are the very few men outside of scientific studies who have been circumcised after entering adult sexuality, either for religious reasons or for personal preference. Erik Janssen of the Kinsey Institute in Bloomington, Indiana, wants more work to be done: “I think we need quite a bit more data on the direct effects of circumcision on penile sensation,” says Janssen. “Is it leading to additional types of stimulation that are more pleasurable? I don’t know of really good research on this topic; if there was funding for it, I would study it.”
And all the research in the world doesn’t mean that there aren’t people out there who would rather have things the other way around; there are. There’s actually a bit of a cottage industry developing that specializes in reversing circumcision. So maybe there’s more to having a foreskin than we currently and fully understand.
But there’s another possible reason for the practice of male circumcision. Those ancient desert dwellers may have believed circumcision could prevent infection. If they did, there’s new evidence that they were right, although not in the way they imagined, about a disease they likely would not have encountered, and in a way they couldn’t have conceived.
For some years Dr. Daniel T. Halperin, of the Harvard School of Public Health, has been pushing the idea that circumcision can help prevent the spread of HIV. And he isn’t the only one. More than twenty years ago, not long after AIDS was first identified, a urologist named Dr. Aaran Fink suggested the same thing. For a long time, they and others who shared their belief were ignored or even ridiculed.
But there’s nothing like a little data to change people’s minds.
A seven-year study in India, conducted from 1993 to 2000, found that circumcised men were seven times less likely to contract HIV. But that study had serious methodological flaws, because it didn’t take into account factors like education and economic status, both of which are already associated with a higher incidence of circumcision and safer-sex practices.
How Sex Works Page 5