This story appears in the January 2017 issue of National Geographic magazine.

Shadrack Nyongesa’s appointment with the knife was set for shortly after dawn.

Since the previous morning, the uncircumcised 14-year-old from the Bukusu tribe in western Kenya had been jingling a pair of feathered cowbells against metal braces lashed to his wrists. As he pumped his arms and danced on a dirt yard under a mango tree outside his father’s house, older friends and relatives paraded around him brandishing sticks and guava branches and singing songs about courage, women, and alcohol.

In the afternoon Shadrack and his entourage made a ritual visit to the home of a maternal uncle, who gave him a cow, but not before slapping him in the face and barking that he looked like a sissy, not someone ready to become a man. The boy, who had asked to undergo sikhebo, the Bukusu circumcision ceremony, could not hold back tears. But he looked more angry than afraid, and when he returned to his father’s house, he jingled the chinyimba bells with new vigor and danced with the brio of a bravura showman.

View Images Drew Moore plunges a knife into a wild hog’s heart while his dad, Peaty, and their dog hold the animal. This is a primordial, intimate form of hunting and one that puts meat in the family’s freezer. Drew, who’s been “sticking hogs” since age six, says when he grows up, he wants to be a biologist.

By sundown the party had swelled to more than 50 guests. Men sitting in lantern-lit huts dipped long, reedlike straws into a communal pot of busaa, the corn beer specially brewed for the occasion. At half past nine the crowd formed a circle around the pearly blue guts of a freshly slaughtered cow. One of Shadrack’s paternal uncles sliced open the bloated stomach with a knife. He carved two strips of tissue, then scooped out a handful of greenish, half-digested food. He approached his nephew with his arm cocked.

“No one in our family has ever been afraid!” he shouted. “Stand firm!” Flashlights played on Shadrack’s face as he stared into space with the miserable stoicism of a plebe on his first day of military school. And then, in a moment that impressed even people who had seen it many times, the uncle flung the foul porridge at his nephew’s chest and zealously began to spread it on the boy’s face and head. He placed the collar of cow gut around Shadrack’s neck and slapped him hard on both cheeks.

“If you fidget or cry out, don’t come back,” the uncle said. “Cross the river, and keep going. You are a soldier now. If someone pokes you in the eye, you do not blink!”

For the omusinde—one who is not circumcised—there was now no turning back.

For hours that night, Shadrack danced in the eye of the busaa-fueled revel called the khuminya. Elders counseled him on what it meant to be a man, offering moral precepts, explaining the importance of respecting elders and women, and issuing practical advice including an admonishment to steer clear of married girls. He had been given flour, chickens, and small sums of money. His worthiness had been taunted, his resolve questioned. Around midnight he was finally allowed to lay his leaden arms and dung-crusted head down for a rest. He rose at 2 a.m. An hour later he was again doggedly jingling the chinyimba bells and dancing in what seemed the throes of adrenaline. The relatives and friends—some of them pie-eyed from the homemade beer—sang out, “The sun is about to get up! Can you smell the knife? The dawn is almost here!”

View Images After hiking 55 punishing miles over five days on the Appalachian Trail, Victor Rivera embraces a classmate. Their all-male high school, St. Benedict’s Prep in Newark, New Jersey, teaches a conscientious view of masculinity. The school motto: “Whatever hurts my brother hurts me; whatever helps my brother helps me.”

As I stood waiting for the sun to rise over the Great Rift Valley and the climax of Shadrack’s passage to manhood—a passage crucial to William, his father, whose standing in the community was at stake—I couldn’t help but think of my own father, who had died in June at the age of 91, and my 17-year-old son, Oliver, who at that moment was asleep 7,000 miles away, in New York City. Actually, probably not asleep. Probably lying awake in bed with his laptop on his chest, watching sports documentaries and Hollywood movies bootlegged off sketchy websites.

It was impossible to imagine two roads more different for a pair of boys heading toward essentially the same destination. Both Shadrack and Oliver had been masculinized in the womb by a prenatal bath of testosterone. Both were in the midst of a momentous transition, morphing under a fresh influx of the powerful hormone into physically mature men: body hair, defined muscles, bigger shoulders, burgeoning sexuality, an appetite for risk, potentially elevated levels of aggression. Both were coming to grips with behavioral tendencies and patterns that had been programmed by millions of years of evolution.

But Shadrack was entering manhood in a culture in which the roles of men and women are still slotted along traditional lines and boys are guided by a ritual that goes back at least 200 years (and immemorially in some neighboring tribal cultures). Oliver, on the other hand, is approaching manhood in an American culture that is lurching toward a gender-neutral society, one that has moved so far from anatomy-based definitions of men and women that the U.S. Departments of Justice, Education, and Defense in 2016 affirmed antidiscrimination policies that recognize a person’s self-assigned gender identity, regardless of the sex ticked on a birth certificate.

Unlike Shadrack, Oliver cannot rely on the traditional roles of men and women for an idea of what it means to be a man. In the name of equality, gender stereotypes have been turned inside out or repudiated. There’s nothing startling or unorthodox to him about female cops or male nurses or about a father who stayed home microwaving stockpiles of breast milk while mom went to an office as the prime provider. Oliver’s mom still outearns me and, by the way, has amassed a vastly larger number of Instagram followers.

Nor are there, in our milieu, rituals or overt rites of initiation that would clearly mark Oliver’s transition from boy to man. Manhood, in other words, is something he pretty much has to figure out for himself. Sometimes I see him casting about for what it means, looking askance at the example I set because, as he says, “you cross your legs like a girl.” And sometimes when he’s under duress, feeling pressure to perform—quizzes, papers, grades, competition on a basketball court, a time trial on a rowing machine—I can also see him cultivating a sort of stoicism, related in a milder way to what was slapped into Shadrack. Oliver is shy, careful not to show the depth of his feelings lest he appear unmanly. He gave up the flute because he was the only boy in the section. He crosses his legs ankle to knee. His icons of manhood are Michael Jordan and George Clooney. For his 15th birthday, he asked for a suit.

View Images Enveloped by the men of his family and Hasidic faith, Levi Tiechtel celebrates his 13th birthday at his bar mitzvah in Queens, New York. For millennia, Jews have been performing this ritual, which commemorates the age when a male becomes accountable for his own actions and sins.

View Images Members of Comandos de Salvamento enjoy downtime between calls to render emergency services in San Salvador, El Salvador. These boys have rejected the violent gangs that have seduced many of their peers, opting instead to express their manhood by helping those in need.

Scientists and scholars can’t offer him, or any of us, much clarity. The questions surrounding manhood and its kindred concepts of manliness and masculinity have been embroiled for centuries in politically inflected debates about culture and biology. Anthropologists and sociologists generally come down on the side of culture, believing that manhood is something societies construct. “Men” are made, not born, argues Michael Kimmel, a professor of sociology at Stony Brook University: “Manhood is not a manifestation of an inner essence … [it] does not bubble up to consciousness from our biological constitution; it is created in our culture. In fact the search for a transcendent, timeless definition of manhood is itself a sociological phenomenon—we tend to search for the timeless and external … when the old definitions no longer work and the new ones are yet to be firmly established.”

Some feminist scholars and scientists have argued that gender differences are fabrications and so-called male traits are no more intrinsic to boys than the blue Onesies snapped onto male newborns in the hospital. No doubt that’s the case for many gender stereotypes about differences in male and female intelligence, nurturing instincts, rationality, emotions. But like most parents who have raised a boy and a girl, I have to wonder if there isn’t something more than cultural socialization behind behaviors that seemingly appeared without any conscious priming from mom and dad, or anyone else. I’m thinking of Oliver’s very early zeal for throwing balls around—Nerf balls, tennis balls, ball-shaped agglomerations of masking tape. In the streets of Paris we once played catch with a chestnut. By the same token, might there have been something deeper than cultural socialization behind his sister, India’s, penchant for staging elaborate sotto voce conversations between her dolls? Long before she went off to preschool, she would hold a doll in either hand and pass hours whispering doll dialogue like an interpreter in the middle of a treaty negotiation.

Many Paths to Manhood Throughout history, cultures have devised myriad practices and rituals to make boys into men. The methods—often secret and sacred—vary widely and continually evolve, says cultural anthropologist Gilbert Herdt. But they also share some universal themes that broadly reflect a community’s values and the roles its men are expected to play. TAP IMAGES FOR MORE Strength and

Resolve Marriage and

Children Pledging

Fealty Inherited

Status Performing

Religious Rituals Extreme Masculine Behavior Sparta - 800 B.C. At seven, Spartan boys left their families for boarding schools to test their strength and resolve. Military training included forming erotic bonds with older boys to encourage loyalty in battle and enduring severe beatings to build toughness. Now: Many cultures promote tests of strength. Boys in Papua New Guinea’s Sambia tribe are separated from their mothers at age seven and must undergo secret initiation rites involving nose bleed­ing and performing oral sex on men. Rome - 27 B.C. With Rome maturing as an empire and slaves outnumbering citizens, boys in their mid-teens were urged to marry early and produce children. Only then would they be considered men and full citizens with rights and status. Now: In numerous societies marriage remains primarily defined as a religious ritual that, for young men, can be con­sidered an entry into adult maturity, morality, and masculine social roles. England - 1600 A teenage squire’s road to knighthood required apprenticing with a knight, pledging fealty on a holy artifact to the king, competing in fighting and jousting matches, being confirmed as a Christian, and joining a Crusade to the Holy Land. Now: In the Pacific’s Trobriand Islands, a pubescent boy leaves his family to join a group house and be tutored by a maternal uncle. Submitting to this mentor shows respect for his ancestors and commitment to his community. Hawaii - 1700 Boys from high-ranking families served close to the king and inherited their status as adults. If a teen from a lower status family fought well in battle or demonstrated healing powers, he might earn non-­inherited status as a warrior, priest, or magician. Now: In contemporary India, lower caste Hindu males try to prove their piety and courage and gain status through rituals, such as walking barefoot over burning coals during festivals or wrestling bulls at harvest celebrations. Great Plains - 1900 A Lakota teenager would be old enough to perform religious rituals such as the Sun Dance. Men and boys taking part in this rite had to stare at the sun while being supported by ropes attached to pegs pierced through their skin. Now: Boys of Liberia’s Kpelle tribe are secluded for four years of secret initiations, instruction, ritual circumcision, and male-only ceremonies said to have been created by the gods for men to gain supernatural powers needed for survival. Italy and U.S. - 1930 In Sicily and Chicago, Mafia groups gave rise to extreme masculine behavior, defined by violence and terror, and conditional masculine behavior, where status depends on being in the group and leaving can mean the loss of manhood, or even one’s life. Now: Terrorist groups such as ISIS demand that initiates commit acts of extreme violence. They often force members to disavow traditional markers of manhood, such as upholding responsibilities to their families and communities. DANIELA SANTAMARINA, NGM STAFF. ART: VIKTOR MILLER GAUSA </br>SOURCE: GILBERT HERDT, SAN FRANCISCO STATE UNIVERSITY

“Women and men do not have interchangeable minds,” notes Harvard psychology professor Steven Pinker in his book The Blank Slate. Consistent with the selection pressures of having to compete for resources and mates, studies going back decades suggest males do better on mental tasks that involve rotating an object. (Girls have advantages in other problem-solving skills.) Boys tend to be more physically aggressive—more likely to engage in what’s called “rough-and-tumble play.” As Joe Herbert, emeritus professor of neuroscience at the University of Cambridge, notes, boys will play with dolls, but chances are the dolls will be getting into a fight.

Some aggressive behavior can be linked to testosterone levels, which, starting around age 10 and peaking in the late teens, are typically more than 10 times higher in boys than in girls. One revealing study published in 2013 in the Journal of Cognitive Neuroscience correlated risktaking behavior with testosterone levels in adolescent boys and girls. The kids in the study could win money by clicking a pump that inflated balloons. But if the balloons exploded, as they were programmed to do randomly, the players would forfeit their winnings. The researchers found that increased testosterone levels were associated with risktaking in both boys and girls. But the boys preferred the thrill of balloon explosions, even though it cost them cash, while the risktaking girls with relatively elevated testosterone levels were more interested in retaining their earnings.

Perhaps one of the clearest examples of how biology underlies many elements of masculinity and thus is a factor in the cultural construction of manhood is a rare genetic condition called androgen insensitivity syndrome. Babies are born with a Y chromosome and therefore biologically male, but their bodies can’t process testosterone and so default to the female phenotype. They have features and traits of a woman, smooth hairless skin, minimal body odor, a rudimentary vagina. They feel themselves to be women. But with internal testes instead of ovaries and a uterus, they can’t give birth. The syndrome, Herbert notes in his book Testosterone, is “a glaring demonstration that testosterone is at the root of what we call ‘masculinity.’ ”

And so at first light, on the impetus of both Bukusu cultural imperatives and what scientists say is upwards of 1,200 nanograms per deciliter of testosterone coursing through an adolescent male’s bloodstream, Shadrack headed north on foot for the nearby Chwele River. He was surrounded by more than 30 men and boys, and a few cheeky girls who hadn’t yet been shooed away. Songs flowed as the company jogged along red clay roads and fields of corn and sugarcane. At a quarter to seven, Shadrack’s bells and the metal wrist braces were removed. The boy stepped out of his tan shorts. He walked naked down a grassy bank to what was more a swamp than a river. His uncle followed. Hidden in the reeds, Shadrack washed off the cow slime. When he emerged, he was covered with dark gray mud. A sprig of special grass was plastered to his head like the crest of a northern lapwing.

Now the company headed south back to Shadrack’s father’s house, moving almost at a gallop along a different route to thwart any possible witchcraft by persons of ill will. They sang the anthem of Bukusu-land, the famous sioyayo circumcision song that insults the rival Kenya tribe of the Luo, whose traditional entry to manhood entailed removing some of a boy’s teeth instead of his foreskin. “Those who fear circumcision should go to Luo-land.”

A huge crowd—men, women, girls, boys—was waiting at the compound. Shadrack marched into the yard and stood over a piece of cardboard. He faced west, symbolically overseeing the sunset of his boyhood. Still the showman, Shadrack put his left hand on his hip and thrust his right hand above his head as if he’d been studying the victory celebrations of Usain Bolt. The circumciser crouched at his groin. The operation was over in seconds. Shadrack did not blink or flinch or let on that he felt any pain. In fact, when the circumciser blew a whistle signaling the surgery was done, and Shadrack’s aunt and mother and other women were ululating in joy, Shadrack began to prance about.

Shadrack’s father, his uncle, and others rushed up to inspect the job, bending in for a close-up view as if they were double-checking the numbers of a winning lottery ticket. Shivering, perhaps in shock, Shadrack sat down as women wrapped him in colorful shawls.

He would spend the next four days convalescing. Traditionally, new initiates in this community are sequestered for four months with a guardian who will teach them how to hunt, build a hut, tan a hide, and become warriors fierce enough to repulse attacks from cattle raiders and stage raids of their own. Though some young Bukusu males still learn these skills, Shadrack would be going back to school when classes resumed in September. “You can be fierce in school,” says Simiyu Wandibba, a Bukusu professor of anthropology at the University of Nairobi. “You can repackage traditional virtues to suit today’s life.”

Already Shadrack was being treated with new respect; already he was entitled to a new set of patriarchal privileges. No longer would he be dispatched to fetch water from the river or collect firewood or sweep the family compound. Women preparing his meals now would consider his preferences. With a hut of his own in the family compound, he would no longer sleep in his mother’s house or sit at her feet listening to her stories. And come December, in accord with the old ways, there would be a khukhwalukha ceremony when the traditional period of transition from omusinde to omusani would be complete, and the 14-year-old would be formally presented to Bukusu-land as a full-fledged man.

It's hard to watch a Bukusu circumcision ceremony without being whipsawed by a mix of admiration and dismay. Dismay because the kids are … well, kids. I saw five circumcisions in a week, and some of the omusinde were even younger and looked less ready for the ordeal than Shadrack. Is a boy of 10, tempted by the promise of new privileges and pressured to conform, really free to make the decision to undergo this painful and potentially dangerous surgery? And what was done to Shadrack and the others is hardly the extreme of what cultures do to make men of boys. Mardudjara aboriginal boys in Australia are expected to swallow their own foreskins after the cut. Sambia mountain boys in Papua New Guinea push sharp sticks into their nostrils to make their noses bleed and have to swallow semen after oral sex with young men. Satere Mawe boys in the Brazilian Amazon insert their hands into gloves filled with bullet ants (Paraponera clavata) whose neurotoxic sting is said to be among the most agonizing in nature.

It’s worth asking: Why? The disquieting answer, of course, is to prepare for war. As anthropologist David Gilmore notes, where resources are scarce and the collective welfare uncertain, “gender ideology reflects the material conditions of life.” Boys are “tempered” and “toughened” so they may fulfill the classic duties to procreate, provide, and protect that men have performed for millennia. Whether it’s marshaled to ward off the aggression of other males or to capitalize on weakness, violence is the leitmotif of manhood in countless cultures. To judge from video games, action movies, hockey brawls, UFC fights, and homicide rates in America, violence enthralls men even where material conditions of life are not dire.

What could break the cycle that equates manhood with toughness and stoicism? What might change in men who in their fear of violence—or fascination with it—end up fostering more of it?

Dismay aside, I found it hard not to grudgingly admire a culture that gives boys such an unambiguous path to manhood. The steps are clearly marked. The knife and the cut undeniably make the whole business real. “The blood connects us to our ancestors,” one of Shadrack’s uncles told me. Shadrack’s male privileges may entitle him to the supper he prefers, but they also come with obligations and responsibilities, and by some lights the abuse in the ritual may actually help teach the boys not to respond in kind. “If you’ve literally had cow shit thrown at you, you know you can take whatever life throws at you,” says Daniel Wesangula, a Bukusu journalist.

Add to that the support from bakoki, the brotherhood of boys who have been circumcised at the same time and belong to the same age-group. “Bakoki are lifelong friends,” Wesangula says. “They will carry your casket and dig your grave. If you are acting deviant, parents will send a bakoki to put some sense into you.”

It might be for the lack of meaningful manhood rituals that Oliver’s school recently invited a youth theater group to perform a play called Now That We’re Men. Among the questions on the program: “Who is harmed when [sexual slurs] are thrown around constantly in middle and high school hallways? What is it like to participate in a culture where the most popular video games on the market today award points when players (mostly young males) rape and kill women?”

If my son is uncertain about what it means to be a man, I suppose I’m partly to blame for passing along the tradition of unstructured self-discovery that I inherited from my father, who did not buttonhole me for mortifying talks about birds and bees, or show me how to knife a wild hog, or concoct the Connecticut atheist’s equivalent of a bar mitzvah. I don’t know what passed for rituals that ushered me from boyhood into whatever it is I embody now, with a roster of half-baked competencies and a list of things I still can’t do. Rewire a lamp. Shuck an oyster.

In my father’s final months last spring, I asked him if he had tried to prepare me for manhood, and when he looked baffled, I asked him if he thought his father had done anything to set him up. More bafflement. I imagine his manhood came courtesy of the U.S. Navy. Toward the end, he couldn’t remember at noon what medical procedures had been performed on him at 11:45 a.m., but he could recall all the shipmates he served with during World War II. He was 19 when he crossed the Pacific on an oceangoing tug. He navigated by sextant, boxed with fellow sailors, and off Okinawa fired his sidearm at a kamikaze. He sailed into Hiroshima Bay two months after the atomic bomb and saw the starkest consequences of men at war, an experience that inspired him to compose a poem that was published in October 1945 in the New York Herald Tribune. It earned him $12, his first wages in a long career as a writer. Protect. Provide. I found a photocopy of the check in his files after he died.

Absent rituals, I think manhood in my family must be a code of values, transmitted mostly by example. My father once explained to one of my college roommates, whose family had a ranch in Wyoming, why he didn’t need a gun to protect his family. In a line that now seems not just the high-water mark of a certain kind of liberal idealism but looms as central to my father’s idea of manhood itself, he said: “The day I reach for a gun instead of a lawyer, there will be nothing left to defend.” That seems almost quaint now in an age when man-boys are trotting to class at the University of Texas with pistols in their pants. And I wonder if there is a manhood ritual artful enough to convey the values my father saw in the two artists who shaped his sensibility—the humorist Robert Benchley and the great trumpeter Louis Armstrong—both of whom he revered for their “humor, decency, and joie de vivre.”

I don’t know how useful it is for Oliver to know there are a million definitions of what it means to be a man or that he is free to choose his own, to figure out on his own what it takes for a boy to qualify. I hope he grasps the responsibilities manhood entails and rejects the inequities it perpetuates and understands what part is biology, what part culture, what’s estimable and worth conserving, what cries out for change. I hope he becomes a man however he manages to define it and expects no special dispensation for fulfilling that vision of himself. He too has a bloodline of ancestors, somewhere out there in the dust. He could do worse than to set his compass by the polestar of humor, decency, and joie de vivre.