The night before Susan and Rob allowed their son to go to preschool in a dress, they sent an e-mail to parents of his classmates. Alex, they wrote, “has been gender-fluid for as long as we can remember, and at the moment he is equally passionate about and identified with soccer players and princesses, superheroes and ballerinas (not to mention lava and unicorns, dinosaurs and glitter rainbows).” They explained that Alex had recently become inconsolable about his parents’ ban on wearing dresses beyond dress-up time. After consulting their pediatrician, a psychologist and parents of other gender-nonconforming children, they concluded that “the important thing was to teach him not to be ashamed of who he feels he is.” Thus, the purple-pink-and-yellow-striped dress he would be wearing that next morning. For good measure, their e-mail included a link to information on gender-variant children.

When Alex was 4, he pronounced himself “a boy and a girl,” but in the two years since, he has been fairly clear that he is simply a boy who sometimes likes to dress and play in conventionally feminine ways. Some days at home he wears dresses, paints his fingernails and plays with dolls; other days, he roughhouses, rams his toys together or pretends to be Spider-Man. Even his movements ricochet between parodies of gender: on days he puts on a dress, he is graceful, almost dancerlike, and his sentences rise in pitch at the end. On days he opts for only “boy” wear, he heads off with a little swagger. Of course, had Alex been a girl who sometimes dressed or played in boyish ways, no e-mail to parents would have been necessary; no one would raise an eyebrow at a girl who likes throwing a football or wearing a Spider-Man T-shirt.

There have always been people who defy gender norms. Late-19th-century medical literature described female “inverts” as appallingly straightforward, with a “dislike and sometimes incapacity for needlework” and “an inclination and taste for the sciences”; male inverts were “entirely averse to outdoor games.” By the mid-20th century, doctors were trying “corrective therapy” to extinguish atypical gender behaviors. The goal was preventing children from becoming gay or transgender, a term for those who feel they were born in the wrong body.

Many parents and clinicians now reject corrective therapy, making this the first generation to allow boys to openly play and dress (to varying degrees) in ways previously restricted to girls — to exist in what one psychologist called “that middle space” between traditional boyhood and traditional girlhood. These parents have drawn courage from a burgeoning Internet community of like-minded folk whose sons identify as boys but wear tiaras and tote unicorn backpacks. Even transgender people preserve the traditional binary gender division: born in one and belonging in the other. But the parents of boys in that middle space argue that gender is a spectrum rather than two opposing categories, neither of which any real man or woman precisely fits.

“It might make your world more tidy to have two neat and separate gender possibilities,” one North Carolina mother wrote last year on her blog, “but when you squish out the space between, you do not accurately represent lived reality. More than that, you’re trying to ‘squish out’ my kid.”

The impassioned author of that blog, Pink Is for Boys, is careful to conceal her son’s identity, as were the other parents interviewed for this article. As much as these parents want to nurture and defend what makes their children unique and happy, they also fear it will expose their sons to rejection. Some have switched schools, changed churches and even moved to try to shield their children. That tension between yielding to conformity or encouraging self-expression is felt by parents of any child who differs from the norm. But parents of so-called pink boys feel another layer of anxiety: given how central gender is to identity, they fear the wrong parenting decision could devastate their child’s social or emotional well-being. The fact that there is still substantial disagreement among prominent psychological professionals about whether to squelch unconventional behavior or support it makes those decisions even more wrenching.

Many of the parents who allow their children to occupy that “middle space” were socially liberal even before they had a pink boy, quick to defend gay rights and women’s equality and to question the confines of traditional masculinity and femininity. But when their sons upend conventional norms, even they feel disoriented. How could my own child’s play — something ordinarily so joyous to watch — stir up such discomfort? And why does it bother me that he wants to wear a dress?

Despite the confident tone of the letter Alex’s parents wrote to the preschool parents, Susan was terrified. She feared Alex’s fascination with femininity would make him a target of bullying, even in the progressive New England town where they live. She felt tortured by statistics that indicated gay and transgender teenagers, either of which she figured Alex might become, were much more likely to take drugs and commit suicide. She began having panic attacks. “The whole thing was vertiginous,” she said. “It’s hard to put a finger on why gender identity makes such a difference to our sense of who a person is, but it does. As a parent, it’s really destabilizing when that’s pulled out from under you. And I worried that if I was having a hard time wrapping my mind around my kid, and I love him more than life itself, then how would the rest of the world react to him?”

Relatively little research on gender-nonconforming children has been conducted, making it impossible to know how many children step outside gender bounds — or even where those bounds begin. Studies estimate that 2 percent to 7 percent of boys under age 12 regularly display “cross-gender” behaviors, though very few wish to actually be a girl. What this foretells about their future is hard to know. By age 10, most pink boys drop much of their unconventional appearance and activities, either because they outgrow the desire or subsume it. The studies on what happens in adulthood to boys who strayed from gender norms all have methodological limitations, but they suggest that although plenty of gay men don’t start out as pink boys, 60 to 80 percent of pink boys do eventually become gay men. The rest grow up to either become heterosexual men or become women by taking hormones and maybe having surgery. Gender-nonconforming behavior of girls, however, is rarely studied, in part because departures from traditional femininity are so pervasive and accepted. The studies that do exist indicate that tomboys are somewhat more likely than gender-typical girls to become bisexual, lesbian or male-identified, but most become heterosexual women.

Alex was clearly in that small percentage of boys who trample gender barriers. At age 3, he insisted on wearing gowns even after preschool dress-up time ended. He pretended to have long hair and drew pictures of girls with elaborate gowns and flowing tresses. By age 4, he sometimes sobbed when he saw himself in the mirror wearing pants, saying he felt ugly.

Worried, his mother scoured the Internet for information. She and Rob found much to support their gut impulse to affirm rather than repress their son’s unconventional gender expression. Only a few years ago, such encouragement would have been hard to find, but the gay rights movement has made a big difference. Moreover, the visibility of transgender people — be it running for office or tangoing on “Dancing With the Stars” — has provided an opening for those who fall between genders. Though acceptance is not yet widespread, many school districts and local governments now ban discrimination based on gender identity or expression.

Transgender activists have also pressed for changes in the psychiatric establishment, which still officially considers children’s distress over gender identity a mental illness. Now the American Psychiatric Association is reviewing the diagnosis of “Gender Identity Disorder in Children” for the next edition of the Diagnostic and Statistical Manual of Mental Disorders. Critics, though, condemn the association’s choice of Dr. Kenneth Zucker to lead the inquiry. Zucker is the head of a well-known gender-identity clinic in Toronto and the most prominent defender of traditional interventions for gender nonconformity. He urges parents to steer their children toward gender-typical toys, clothes and playmates and advises them to prohibit behaviors associated with the other sex. Zucker’s academic articles assert that while biology may predispose some children to gender nonconformity, other factors — like trauma and emotional disorders — often play a role. Other contributing causes he cites include overprotective mothers, emotionally absent fathers or mothers who are hostile toward men.

Transgender advocates and sympathetic clinicians argue that telling children in that middle space to abolish their cross-gender interests makes them more distressed, not less. There is also little to no evidence that therapeutic interventions change the trajectory of a child’s gender identification or sexual orientation. Clinicians who oppose traditional treatments contend that significant gender nonconformity is akin to left-handness: unusual but not unnatural. Rather than urging children to conform, they teach them how to respond to intolerance. They encourage parents to accept their children’s gender expression, especially because studies show that parental support helps to inoculate gender-atypical children against ostracism and deflated self-esteem.

Just how many parents choose this approach over the traditional no-tolerance one is unknown. What is clear is that in the last few years, challenges to the conventional model have become increasingly common in the United States and Europe, in medical publications and among professionals and parents themselves. “The climate has changed,” said Edgardo Menvielle, head of one of the world’s few programs for gender-nonconforming youth, at Children’s National Medical Center in Washington. “A lot of parents don’t even go to clinicians anymore. They go to Web sites and listservs, which influence how they think about gender. More parents decide that making their child conform to a gender will damage his self-esteem, and I’d agree. I would argue it’s not even ethical to say to a child, ‘This is the gender you must be.’ ”

In Washington, Menvielle runs a support group for parents that he founded with a psychotherapist named Catherine Tuerk. When Tuerk’s gender-atypical son was a child three decades ago, she consulted a psychiatrist, who told her to keep her son away from girl toys and girl playmates, and to encourage aggressive behavior. So she and her husband signed up their gentle boy for karate and soccer and took him to psychoanalysis four times a week for years. He became sullen and angry. At 21, he told his parents he was gay. In time, she and her husband viewed their efforts as unwitting abuse. Tuerk vowed to help others avoid the same mistakes.

Alex’s mother, Susan, found Tuerk in her Internet search when Alex first begged to wear a dress to preschool. After a long phone conversation with Tuerk, Susan bought her son a few dresses. To Alex’s irritation, people on the street often mistook him for a girl. “I just hate being misunderstood,” he told his baby sitter. When his parents asked if he wanted them to refer to him as “she,” he said, “No, I’m still a he.”

Susan and Rob wondered if Alex would eventually become transgender. They knew more doctors were giving puberty-blocking hormones to pubescent children considering a transition to the other sex. The hormones not only buy time but also spare the young teenagers the angst of developing secondary sex characteristics that feel terribly wrong to them. Even Zucker supports hormones for teenagers who want to become the opposite sex, because mounting evidence indicates it best eliminates their misery. Yet many question whether adolescents are mature enough to make such life-altering decisions, especially when the drugs’ long-term effects are unknown.

Though Alex was a long way from facing those decisions, the possibility hovered in Susan’s mind as she watched his emotional upheaval that autumn in preschool. He became obsessed with a particular lavender dress and fell apart whenever it was in the wash. Alarmed, Susan and Rob decided to limit dress days to Tuesdays and Saturdays, telling Alex he couldn’t fairly expect them to launder it more often. Their fuller reason was more complicated. For one thing, they didn’t have the emotional strength to take him out in a dress every day, to deal with the double takes and the implied judgments. For another, they had noticed how, depending on his mood and his clothing, Alex comported himself in very different gendered ways. While they continued to furnish Alex with toys and activities from all across the gender spectrum, they hoped that more time in boy clothes might help him feel more comfortable with society’s expectations for his biological sex, especially given the likelihood that he’d grow into a male-identified adult.

Still, it was hard not to wonder what Alex meant when he said he felt like a “boy” or a “girl.” When he acted in stereotypically “girl” ways, was it because he liked “girl” things, so figured he must be a girl? Or did he feel in those moments “like a girl” (whatever that feels like) and then consolidate that identity by choosing toys, clothes and movements culturally ascribed to girls? Whatever the reasoning, was his obsession with particular clothes really any different than that of legions of young girls who insist on dresses even when they’re impractical? Or any different than tomboys who are averse to those same clothes?

No one knows why most children ease into their assigned gender roles so effortlessly and others do not. Hormone levels might play a role. One hint is provided by a rare genetic condition known as congenital adrenal hyperplasia, or C.A.H. The condition produces high levels of androgens, including testosterone, early in gestation, and can create somewhat male-like genitalia in genetic females. Girls with C.A.H. are typically raised as females and given hormones to feminize, yet studies show they are more physically active and aggressive than the average girl, and more likely to prefer trucks, blocks and male playmates. Though most turn out to be heterosexual, women with C.A.H. are more likely to be lesbian or bisexual than women who weren’t bathed in prenatal androgen.

Genetics might also be a factor in gender expression. Researchers have compared the gendered behavior of identical twins (who share 100 percent of their genes) with that of fraternal twins (who share roughly half). The largest study was a 2006 Dutch survey of twins, 14,000 at age 7 and 8,500 at age 10. The study concluded that genes account for 70 percent of gender-atypical behavior in both sexes. Exactly what is inherited, however, remains unclear: the specific behavior preferences, the impulse to associate with the other gender, the urge to reject limits imposed on them — or something else entirely.

Whatever biology’s influence, expressions of masculinity and femininity are culturally and historically specific. In the 19th century, both boys and girls often wore dresses and long hair until they were 7. Colors weren’t gendered consistently. At times pink was considered a strong, and therefore masculine, color, while blue was considered delicate. Children’s clothes for both sexes included lace, ruffles, flowers and kittens. That started to change in the early 20th century, writes Jo Paoletti, a professor of American studies at the University of Maryland and author of “Pink and Blue: Telling the Boys From the Girls in America.” By then, some psychologists were arguing that boys who identified too closely with their mothers would become homosexuals. At the same time, suffragists were pushing for women’s advancement. In response to these threatening social shifts, clothes changed to differentiate boys from their mothers and from girls in general. By the 1940s, dainty trimming had been purged from boys’ clothing. So had much of the color spectrum.

Women, meanwhile, took to wearing pants, working outside the home and playing a wider array of sports. Domains once exclusively masculine became more neutral territory, especially for prepubescent girls, and the idea of a girl behaving “like a boy” lost its stigma. A 1998 study in the academic journal Sex Roles suggests just how ordinary it has become for girls to exist in the middle space: it found that 46 percent of senior citizens, 69 percent of baby boomers and 77 percent of Gen-X women reported having been tomboys.

These days, flouting gender conventions extends even to baby naming: first names that were once unambiguously masculine are now given to girls. The shift, however, almost never goes the other way. That’s because girls gain status by moving into “boy” space, while boys are tainted by the slightest whiff of femininity. “There’s a lot more privilege to being a man in our society,” says Diane Ehrensaft, a psychologist at the University of California, San Francisco, who supports allowing children to be what she calls gender creative. “When a boy wants to act like a girl, it subconsciously shakes our foundation, because why would someone want to be the lesser gender?” Boys are up to seven times as likely as girls to be referred to gender clinics for psychological evaluations. Sometimes the boys’ violation is as mild as wanting a Barbie for Christmas. By comparison, most girls referred to gender clinics are far more extreme in their atypicality: they want boy names, boy pronouns and, sometimes, boy bodies.

Some cultures develop categories for those whose behavior doesn’t fit gender conventions. In Samoa, biological males who adopt feminine mannerisms are accepted as a third sex, called fa’afafine. In the U.S., some who occupy that “middle space” call themselves “genderqueer,” but it is hardly a well-established cultural concept.

“People rely on gender to help understand the world, to make order out of chaos,” says Jean Malpas, who heads the Gender and Family Project at the Ackerman Institute in Manhattan. “It’s been a way of measuring someone’s well-being: ‘Are you adjusted? Do you fit? Or are you unhinged?’ The social categories of man/woman, boy/girl are fundamental, and when an individual challenges that by blurring the lines, it’s very disorienting at first. It’s as if they’re questioning the laws of gravity.”

So it is for Moriko and her husband, who struggled for years to understand their son’s attraction to girls’ clothes even though it made him a social pariah. “I was sad and I was scared, really scared,” Moriko said. “This kind of stuff is not in ‘What to Expect When You’re Expecting.’ I didn’t know what to do, what to think or what was going to happen.” They took their 7-year-old son to a New York City psychologist, hoping for guidance and support. Instead, the therapist blamed them for their son’s femininity, saying Moriko was emotionally detached and her husband too absent. She advised them to confiscate the boy’s dolls and girlish clothes and to find him male friends. They followed her instructions, but their son was miserable, and they ultimately rejected the therapist’s analysis. “It became clear this couldn’t be the right way,” Moriko said. “It was damaging all of us.”

By the time her son was 9, Moriko and another mother had started a support group for families looking to accept, not change, their children’s gender expression. They offered one room for parents to talk and another for the children to play. Today more than 20 families are in the group. A few of the kids now take hormone blockers. A few others have come out as gay. Moriko’s son is still wavering.

Moriko’s son will soon enter eighth grade in his Long Island public middle school. Most of his friends are girls, and he dresses just like them: skinny jeans, black eyeliner, light lipstick and off-the-shoulder shirts from the girls’ department. (Moriko makes him wear a tank top underneath.) When his teachers asked which pronoun they should use when referring to him, he said masculine. But he doesn’t want to be called a boy, or a girl.

“This is a kid who is smack in the middle,” Moriko said. “His feet are getting bigger, his voice is starting to deepen. He doesn’t want to start blockers. We don’t really know what’s next.” She sighed and then started to cry. “His therapist said to me, ‘I know you’ve been living without a gender box for a very long time, and I know it’s frustrating and confusing, but right now, he just doesn’t want to be in a box.’ I’m not trying to label him, but it’s hard not to wonder what he is, if he’s not a boy and he’s not a girl. Sometimes I worry that not being in a box isn’t healthy, either, even if the box is ‘gay’ or ‘genderqueer.’ I just want to be able to wrap my head around some concept. I know I have to be patient, but sometimes I feel like an emotional hostage, because as his parent, it’s my job to help him be whatever he wants to be, and I can’t do that if he doesn’t know where he’s headed.”

Gender nonconformity is a touchy subject, and parents who celebrate it in their children can be judged harshly. When J. Crew ran an ad of its president painting her son’s toenails neon pink, with copy that read, “Lucky for me, I ended up with a boy whose favorite color is pink,” one commentator said she was exploiting her son “behind the facade of liberal, transgendered identity politics.” Then there was Kathy Witterick and David Stocker, the Toronto couple inadvertently caught in a critical spotlight when word spread that they wouldn’t reveal their newborn’s sex because they wanted to free him or her from gender expectations. The idea came from their 6-year-old son, Jazz, who has insisted for the last three years on picking his clothes from the girls’ section of the store.

“I didn’t go into parenting thinking I wanted to deconstruct the notions of gender with my children,” Witterick told me. “I had enough life experience to know that the way we construct masculinity sets men up to either be victimized because they’re wimps, or to be victimizers to prove they’re not. But I will freely admit to you that the first time Jazz selected a dress off the store shelf, I did not know what to do. There were beads of sweat on my forehead.”

Ellen R. and her 10-year-old son, Nick, live in a small New Jersey suburb. Nick sometimes spends hours a day drawing gowns for his 36 Barbies and designing them for himself or his dolls, using fabric, ribbon and rubber bands. For a while, Nick was able to keep his interest hidden. But one day in second grade, a friend stopped by unexpectedly and saw Barbies sprawled in the living room. The boy ran out of the house. In school the following day announced to the class, “Nick plays with dolls.”

“Everyone looked at me,” Nick told me. “I wanted to yell, but you’re not supposed to yell in school. So I said it wasn’t true. But no one believed me.” He was quiet for a while, concentrating on an uncooperative lock of a Barbie’s hair. “He was my friend. That was the worst part of it.”

In the two years since, Nick hasn’t had a single play date.

Ellen’s conviction that Nick shouldn’t be ashamed of who he is runs deep. Yet she nonetheless battles a fear of being shunned. “When your kid’s girly in preschool, the other parents might think it’s cute. But it’s not cute once your kid is in elementary school, especially the older he gets. I sit next to parents at events, I volunteer with the P.T.A., and it’s hard not to wonder, are they out there making fun of me and my kid?”

For other parents, the discomfort is even more intense. When Jose was a toddler, his father, Anthony, accepted his son’s gender fluidity, even agreeing to play “beauty shop.” But as Jose got older and it became clear his interests weren’t just a passing phase, Anthony recoiled. He struggled with confusion, disappointment and alienation from his own child, who called himself a “girl-boy.” Though Anthony tried to hide it, he often cringed when he saw Jose prancing in a neighbor’s flowered dress or strutting in a friend’s wig.

Sometimes, Anthony fled wherever Jose was playing. Other times, he confronted his boy. If Jose walked outside carting a Barbie, Anthony would scowl: “Do you have to carry it allthe time?” Once when Jose was 3 and wearing a dress every day, Anthony pleaded: “Jose! You’re a boy! You’re not a girl — you’re a boy!” and then started to cry. Jose slipped out of bed, padded over to his weeping father and patted his head. “I just didn’t know how to relate to him,” he recalled recently. “I didn’t know how to be the father of a girl inside a boy’s body.”

Anthony and his wife, who live in New York, found a supportive listserv and began seeing a psychiatrist, who urged them to allow Jose to play with toys of his choosing. In a therapeutic compromise, he suggested letting Jose wear whatever he wanted at home, but restricting dress-wearing in public to shield him from derision. The summer after kindergarten, Jose and Anthony attended a retreat for gender-atypical children. Seeing how happy the boys were running around in girly clothes affected Anthony deeply. Afterward, he and his wife joined a support group and enrolled Jose in a prestigious ballet school, where he is thriving. His talent makes Anthony proud.

Jose is almost 9 now. He’s interested in Legos and in cartoons of boys who fight crime and evil aliens. He rarely reaches for a dress, and he’s happy to be a boy, but he still plays with dolls. Anthony is fine with all that, though he reluctantly admits that he’s still distressed when his son talks or moves flamboyantly, and he’s not sure why. Anthony has apologized to Jose. “I’ve told him that I was just close-minded. I say: ‘I really didn’t get it. I didn’t know anybody like you, so it took me a while to get used to it. And I’m really sorry.’ And more than once, he’s said, ‘I forgive you.’ ”

Boys and men do have more latitude these days to dress and act in less conventionally masculine ways. Among straight men, long hair and (certain) necklaces and (certain) pairs of earrings are almost normative, at least in some communities. Plenty of men wax their eyebrows, get manicures and wear pink. In some parts of the country, these shifts have provided an opening for boys who buck some gender norms.

James, for example, is a 14-year-old boy who from age 5 to 10 had long hair, wore feminine clothes and was frequently mistaken for a girl. It was an error that seemed neither to bother nor delight him. By fifth grade, though, he had abandoned most of his skirts. A year later, he was so adamant about being known as a boy that he ordered his parents never to mention his feminine past around his friends.

James is now nearly six feet tall, and his voice is low. His hair still falls down his back, and he dyes the ends pink. When he is with male buddies, they play video games and create digital animé characters. When he’s with female friends, they playact, using wigs and high voices. They brush and braid one another’s hair.

At a coffee shop near their Cambridge home, his father told me that he initially discouraged James from wearing dresses in public as much to protect his own ego as that of his son. But his embarrassment has long since turned to pride. “He’s just this very brave person,” the father said. “I’ve learned so much from him. . . . In college I remember wondering why the femme gay guy wouldn’t just act more butch so people wouldn’t give him a hard time. I didn’t think it was right for people to give him a hard time, but I thought, Hey, you bring it on yourself. Now I know that’s wrong. My son showed me this is part of core identity, not something people just put on or take off. And it’s not their job to make sure we’re all comfortable.”

One day this spring I went to a playground with an 8-year-old boy named P. J. A pink ribbon with sparkly butterflies held back his thick black curls, which he occasionally flipped dramatically. He was wearing a serpent-and-skeleton bike helmet, a navy Pokémon T-shirt, black-and-pink stretch pants, a fuchsia sweatshirt and an iridescent heart necklace. As he and a friend raced happily around the park in a loud game of tag, they accumulated new pals.

After playing for half an hour, a few kids huddled to catch their breath and finally introduce themselves. One 10-year-old girl’s eyes opened wide. She turned to me, the closest adult. “Do you know she’s a he?” Yes, I nodded. Certain that I’d misunderstood, she pointed at P. J., who was right next to her. “No!” she said. “She is a he!”

P. J.’s parents allow him to wear dresses in public, which he does judiciously, based on how likely it is he’ll be hassled. (Yes to the dentist’s office; no to his grandparents’ place.) In school, however, his parents say he can wear anything but dresses, figuring that one item has more TNT than all pink and sparkly things combined. P. J. told me he wears “girl” shirts (he used his fingers to make quote marks) three days a week and “boy” shirts the other two. Most of the time, he chooses pants that are pink or purple. Despite the fact that his parents paid for a half-day of gender-diversity training for the staff at P. J.’s school, he is still sometimes teased on the bus or during recess. “Some of the boys in school make fun of me,” he says. “They keep asking,” and here he switches to a whiny voice, “ ‘Are you a boy or a girl? I forgot.’ And then they ask again the next day. They can’t just forget after one day. They’re just trying to be mean. They say I should cut my hair because it makes me look like a girl, and looking like a girl is bad. It’s not their business, but they say it anyway.”

P. J.’s favorite video game, Glory of Heracles, features an ambiguously gendered character that P.J. described as a girl who wants to be a boy.

“Do you feel like that?” I asked him one day at his house.

“No, I don’t want to be a girl,” he said, as he checked himself out in his bedroom mirror and posed, Cosmo-style. “I just want to wear girl stuff.”

“Why do you want to be a boy and not a girl?” I asked.

He looked at me as if I were daft. “Because I want to be who I am!”

By way of explanation, he told me about a boy in his third-grade class who is a soccer fanatic. “He comes to school every day in a soccer jersey and sweat pants,” P. J. said, “but that doesn’t make him a professional soccer player.”

He’s right: no one looks twice at the soccer-star wannabe, whereas boys like P. J. or Alex are viewed with distress, especially the older they get.

For that reason, last summer, as Alex’s parents contemplated his start at the local elementary school, they feared children there might bully him. So they decided to forbid dress-wearing to kindergarten. Alex didn’t take it too hard. By then, his dress requests had petered out to every few weeks anyway, and he typically wore boy clothes, though he still liked wearing a rainbow-bead necklace and nail polish. Besides, his parents had told him that socks, shoes, nail polish and jewelry were up to him — a way to express himself while safely testing the waters.

Toward the end of the first week of kindergarten, Alex showed up in class wearing hot-pink socks — a mere inch of a forbidden color. A boy in his class taunted, “Are you a girl?” Alex told his parents his feelings were so hurt that he couldn’t even respond. In solidarity, his father bought a pair of pink Converse sneakers to wear when he dropped Alex off at school.

Alex’s teacher, Mrs. C., jumped in, too. During circle time, she mentioned male friends who wore nail polish and earrings. Mrs. C. told them that when she was younger, she liked wearing boys’ sneakers. Did that make her a boy? Did the children think she shouldn’t have been allowed to wear them? Did they think it would have been O.K. to laugh at her? They shook their heads no. Then she told them that long ago, girls weren’t allowed to wear pants, and a couple of the children went wide-eyed. “I said: ‘Can you imagine not being able to wear pants when you wanted to? If you really wanted to wear them and someone told you that you couldn’t do that just because you were a girl? That would be awful!’ ” After that, the comments in the classroom about Alex’s appearance pretty much stopped.

It took Alex several weeks to rouse his courage again. And then, about once a week, he would pull on his pink socks and sparkle kitten sneakers and head boldly off to kindergarten.