Pieces of the Puzzle

It is not the most cherished childhood photo in his mother’s collection, but it may be the most prescient.

The little boy, not quite 2, is perched on a potty seat. A mop of brown hair frames a face with delicate features and big brown eyes. He is wearing a pretty white sundress purloined from his older sister’s closet, a “very girly” frock, according to his mother, that is one of his two favorites. Secreted away elsewhere in the house are the little boy’s other passions: his mother’s fancy shoes and jewelry, his sister’s Barbie doll. And behind the lens is mom, a college professor from Toronto, “collecting evidence” that she can take to the pediatrician.

The boy in the photo, now nearly 15, is contemplating his sexual orientation with the same secretiveness that he once used to hide his penchant for cross-dressing. On the phone, he gabs with his many girlfriends about their current crushes, adopting their incredulous, eye-rolling gestures and their distinctive, sing-song mode of speech. About his own crushes, however, he is mum.

His mother, who demanded anonymity in the interests of her son’s privacy, has no doubt about the young man’s future sexual orientation. “I’m sure he’ll end up being gay,” she says matter-of-factly. As a parent, she wishes it were otherwise; being straight is simply an easier life for a young adult, she said. But she loves her son, and it’s clear to her that even before she and her husband adopted him 20 days after the child’s birth, this, simply, was the way he was made.

While scientists have pondered the mystery of homosexuality for centuries, the secret of how homosexuals are made is only now beginning to yield to their inquiries. Long branded a mental illness, attraction to those of the same sex was expunged in 1973 from the list of psychiatric disorders recognized by practicing clinicians. And American society has fitfully followed suit, emboldening many in this long-closeted minority to declare and celebrate their sexual orientation openly.

The drive toward societal acceptance has not dampened many scientists’ zeal to explain one of evolution’s most curious mysteries: Why has a trait that inhibits sexual reproduction endured? To these researchers, homosexuality remains an evolutionary oddity that demands to be explained. Intriguing new research is finding there may be many different pathways to gayness. Those seeking to explain homosexuality traditionally looked for instances of early sexual abuse, emotionally distant parents and other socialization factors to explain a child’s later same-sex attraction.

But researchers from unexpected disciplines such as brain science and audiology are bringing new perspectives to a field long dominated by Freudians, social workers and, more recently, by gay activists. They are uncovering a wide range of possible physical markers for homosexuality--from the way one’s inner ear responds to sound to the shape of one’s hand--that are evident from a child’s first days. These insights not only point to the mechanisms at work in homosexuality: They offer the intriguing and controversial prospect that perhaps in the not-too-distant future, parents like the mother in Toronto could do more than brace for a child’s sexual awakening; they could do something about it.

Still, the science of homosexuality remains in its infancy. For now, there exists only one childhood trait--often exhibited before a child can walk--that strongly predicts homosexuality later in life. It is early behavior that departs markedly and persistently from the boys-and-trucks, girls-and-dolls stereotypes of years past.

For the cross-dressing toddler in Toronto and other boys who show “pervasive and persistently” effeminate behavior, the odds of being gay lie at about 75%, according to J. Michael Bailey, a psychologist and sexuality researcher at Northwestern University in Evanston, Ill. That is a probability of homosexuality 20 times as high as that in the broad population of boys; it is estimated (though hotly disputed) that 3% to 4% of males will grow up to be gay. Among girls, this so-called gender-atypical behavior also is a good predictor of later lesbianism, though the pattern is weaker.

That may disappoint those who hoped science would have disproved a painful stereotype. But strong and sustained gender-crossing behavior is, says Bailey, “about as strong a predictor as exists in the developmental literature.”

Strong as the relationship may be, however, it has major limitations. Most important, researchers stress there is no evidence that early gender-bending behavior is the cause of later homosexuality: In fact, many argue, the early onset of such predictive behavior suggests that for many, sexual orientation may be fixed at birth. The fact that such behavior is more likely to be greeted with horror than encouragement by family and friends is seen as further evidence for that position.

Beyond that, researchers caution, such behavior is far from conclusive. Many adult gay men and lesbians were gender-conformers as children. And many boys derided as “sissies” and girls labeled as tomboys grow up to be straight.

Consistently Fighting Traditional Roles

The distinction, say researchers, is gender-bending behavior that is neither subtle nor temporary. It isn’t “just a phase,” say parents like Angela and James, a couple who spoke on condition their last names not be used.

By the time he was 18 months old, their son, now almost 7, was drawn to his mother’s shoes and scarves. From 3 years old, he “‘would obsess” about the Little Mermaid and Cinderella, mimicking their dresses, their songs and their gestures, according to his parents.

“Being the progressive, modern-thinking parents we were, we thought, ‘Let’s not stereotype,’ ” said Angela, explaining why the couple bought their son a Barbie doll (and a Ken, whom the child pointedly ignored) when he asked for it.

It was a poignant moment of epiphany--the day their then-4-year-old son stood up in a shopping cart and wept at the realization that he would not grow up to be a mommy--that drove the couple to seek treatment for the child’s “gender-identity disorder.” A certain type of treatment, called “reparative” or “conversion” therapy, seeks to steer a gay person toward heterosexual behavior. By contrast, however, treatment for gender-identity disorder focuses on an individual’s confused sense of self, seeking to make them comfortable with their actual gender.

The American Psychiatric Assn. continues to view it as a mental disorder. But because it affects many in the homosexual community, gay activists object sharply to the labeling and treatment of what they call “transgender” behavior, denouncing clinicians’ efforts as “genocide.”

All of which underscores a key point: As a field of research, homosexuality lies at the dangerous intersection of science and minority politics. In this world, every new finding carries added weight. Both gay activists and their detractors--largely Christian conservatives who view homosexuality as contrary to biblical teachings--dissect the work of researchers for political meaning. If gays and lesbians are “born that way”--if homosexuality can definitively be traced to genes or prenatal environment--is being gay a choice? Do lesbians and gay men follow the same pathways to homosexuality? And if scientists can uncover how homosexuals are made, will they not be an important step closer to finding how they can be unmade?

To homosexuals struggling to protect and extend their rights, the answers to these questions may mean the difference between acceptance and intolerance, cultural vibrancy and decline--life and death, even. For even as a majority of Americans tell pollsters they believe homosexuals should enjoy job protections and basic human rights, roughly half of Americans, according to the Gallup Poll, continue to believe homosexuality “should not be considered an acceptable alternative lifestyle.” And only 29% say they would like to see homosexuality “more accepted” in this nation.

Worry for a Child’s Status in Society

For parents in particular, the dilemma of anticipating a child’s homosexuality can be acute. The Toronto mom, whose son started playing with her fancy shoes at about 10 months, is typical: Like many who see the early glimmerings of a child who will grow up to be gay, she insists that as an intellectual, ethical and political matter, she would never consider trying to change her son’s sexual course. But as she assesses the social challenges a gay son will face in life, she echoes the sentiment of virtually all parents interviewed for this article: If her child could magically be remade, she would wish a heterosexual life for him. “It’s tougher to be a gay kid in high school,” said James, whose 7-year-old has been treated for gender-identity disorder. “Geez, it’s not easy being a straight adolescent!”

Although hypothetical for today’s parents, the possibility that future parents may be able to take a pill or tinker with a gene to steer their offspring toward heterosexuality is no pipe dream.

“It’s not a matter of whether” we’ll find homosexuality’s basic mechanisms, “it’s a matter of when,” said Dennis McFadden, a University of Texas specialist on auditory perception. “And parents are going to rush to influence them, possibly before a child is born.”

Indeed, scientists are finding that an individual’s sexual orientation may be most powerfully shaped before birth--both by genes and, as more recent research is showing, by prenatal environment.

In the last two decades, researchers have established beyond much doubt that, like high intelligence, green eyes or a propensity for certain diseases, homosexuality runs in some people’s genes. Northwestern’s J. Michael Bailey, who has conducted much of this research, notes that a male with a gay brother is three to seven times more likely to be gay himself; and a woman with a gay sister is four to eight times likelier to be a lesbian than a female drawn from the broader population.

“The data definitely are not as strong as for other traits such as intelligence or schizophrenia,” said Bailey. But he added that researchers from various disciplines are nearing consensus on this point: Some genetic component to homosexuality clearly exists.

Studies of identical twins--siblings with the same DNA--illustrate both the power and the limitations of genes in homosexuality. A man or a woman is at least 10 times likelier to be gay if his or her identical twin is homosexual; in other words, his or her probability of being homosexual lies between 20% and 50%. But flip that figure over, and it looks far less impressive: Those probabilities still mean that, among identical twins in which one is homosexual, between half and 80% have a heterosexual twin. Having a “gay gene,” if such a thing exists, carries no certainty of being gay.

How else, then, to account for homosexuality?

In the last several years, a welter of new research has begun to point strongly to a developing fetus’ intrauterine environment as a possible incubator of gayness. This new line of research has been scattered broadly across the peer-reviewed journals that collectively make up science’s bazaar of evidence and ideas. But it all started with a little-understood birth-order peculiarity long observed among adult gay men: They tended to be little brothers, frequently in a household full of older boys.

“When I first encountered these early studies, I thought they were so preposterous that I dismissed them out of hand,” said Ray Blanchard, a psychologist at the University of Toronto’s Department of Psychiatry. “It struck me as the most bizarre example of pseudoscience.”

Later, “by accident,” Blanchard said, he happened upon evidence in his work that there might be something to this anecdotal oddity. He began scouring dozens of databases containing data on both birth order and sexual orientation. By the late 1990s, he had established one of the strongest associations with homosexuality in the field.

For a male child, Blanchard found, the more older brothers in his family, the higher the probability that he would be gay. A firstborn male has a likelihood of homosexuality of about 2%. But for a boy with four older brothers, those odds jump to 6%, Blanchard found. In all, he estimated, one in seven gay men owed his sexual orientation to this “fraternal birth order” effect.

An Immune Response That May Grow Stronger

What force was at work here? An intriguing parallel suggested an explanation. “Blue babies,” or babies born with anemia due to incompatibilities with their mother’s blood type, were much more likely to be latter-born males, too. And researchers had established that the “blue baby” effect was the result of a maternal immune reaction to the presence of foreign cells--male cells--in her blood during pregnancy. With each male child a woman carries, that immune reaction grows stronger and so does the probability of a maternal reaction to the blood incompatibility that causes a newborn to look blue from low oxygen.

Blanchard hypothesized that a pregnant woman carrying a male child has an analogous kind of immune response, which grows stronger with each subsequent male fetus she carries. While he is unclear how, exactly, that immune response affects the baby, many researchers coming to the same conclusion surmise that it affects the chemistry of the amniotic soup in which a fetus develops. At a crucial period of fetal brain development, a higher-than average concentration of certain hormones--say, the powerful hormone estradiol--could cause changes in the way the developing baby’s brain is wired. The implications of that chemical shift would likely be evident early. And they would likely last a lifetime.

By the end of the 1990s, other researchers were beginning to posit similar hypotheses on the bases of wildly different data. Researchers already had established that compared with their heterosexual counterparts, gay men and lesbians were more likely to be left-handed. But in Berkeley and in Liverpool, England, a psychologist and a biologist, working independently, were finding that the shape of the hands--a key measure of in-utero exposure to sex hormones--tended to be different too.

Simply put, the ring finger of a heterosexual man’s right hand tends to be much longer than his index finger; in straight women, the two fingers typically appear nearly the same length, with the pointer dipping just slightly below the ring finger.

But John T. Manning, a biologist at the University of Liverpool, found that as a group, lesbians have a hand pattern that looks more like a man’s than like that of a typical straight female, though still not quite as pronounced. “The finding, Manning concluded, “strongly tells us that female homosexuals have had high levels of exposure to testosterone before birth.”

Texas Researcher Takes Another Tack

Manning seemed to be zeroing in on a defining moment in the development of sexual orientation. In the meantime, in Austin, Texas, a very different route brought psychologist Dennis McFadden to the same conclusion.

A psychoacoustics specialist, McFadden has studied group differences in two measures of hearing: otoacoustic emissions--tiny clicking sounds produced by the auditory system in response to stimulus--and auditory-evoked potential, the brain-wave peaks that an individual produces when presented with sound.

From their earliest days, boys and girls score differently on each measure--no surprise, perhaps, since a fetus’ auditory system develops at the same time that hormonal differences peak in the womb and gender differences emerge. But McFadden found that lesbians fell between heterosexual men and women on both measures--a strong sign that they were exposed to higher-than-normal levels of male hormone in utero.

But like Manning in Liverpool and University of California psychologist Marc Breedlove, McFadden turned up a confounding pattern when he tested gay males. In one auditory measure, but not both, homosexual men were “hypermasculinized” compared with heterosexual men: Essentially, their brain wave peaks produced in response to sound were more “manly” than those of the average straight man.

Breedlove, surveying hand shapes with a portable photocopy machine at a San Francisco street fair, had come up with a similar finding. Writing in the journal Nature last year, Breedlove reported that he had been unable to establish a direct relationship between the overall average finger lengths of men and their sexual orientation. But on the basis of their finger lengths, he found that some gay men appeared to have been exposed to greater-than-normal levels of male hormones prenatally.

McFadden and Breedlove had run headlong into one of homosexuality’s most entrenched stereotypes and some of its strongest research. In many cognitive measures, gay men tend to fall between men and women on the continuum of gender differences--they are, according to researchers, “feminized.” Gay men tend to have better language skills, an area where girls generally fare better than boys. And they tend to be weaker in activities that take great spatial acuity, like maze-running and mathematics--areas where boys, as a group, outperform girls.

But here, by contrast, was evidence that some gay men were more “male” than the average male. And it tracked with other, sketchy indications of “hypermasculinization” among a group of male homosexuals: Their average number of sex partners was greater than that of their straight counterparts, the levels of testosterone that circulated in their blood was higher and their genitalia were larger. “This calls into question all of our cultural assumptions that gay men are feminine,” said Breedlove.

Evidence like this has confounded and unsettled the community of researchers as well. With new findings scattered across many disciplines and, at best, a patchwork of explanations for homosexuality emerging, little is settled in this most incendiary of fields.

Within the gay activist community, the jumbled state of research is greeted with conflicting reactions: There is fascination “because these studies help us understand who we are,” said David Smith, a spokesman for the Human Rights Campaign, a Washington-based gay-rights group. And there is a kind of grudging sympathy for the challenges facing researchers, since gay men and lesbians know how complicated and diverse they are. And finally, Smith added, there is a sense that whatever the outcome of research, “it shouldn’t matter, because everyone deserves to be treated with dignity and respect.”

Indeed, the fact that no one researcher has unlocked the mystery of all homosexuals’ orientation suggests there may be many different factors at work.

Gay men and lesbians, in short, come in all varieties, scattered widely across our conventional notions of masculinity and femininity, said Northwestern’s Bailey. “That suggests possibly that there are different bases for homosexuality” in different people, he said.

If they are to continue to uncover homosexuality’s roots, scientists acknowledge, they increasingly will have to look at gay men and lesbians not just as groups, but as individuals. In that sense, they say, they are mirroring the challenges of the larger society. And the sentiments of parents like Angela and James.

“It’s not on my mind that I’m watching our son grow up gay,” said James. His 7-year-old is, he added, simply who he is: a shy child with a backyard fort and, yes, an attraction to Barbie dolls. If he ends up being gay, they will not worry so much about whether it was the fraternal birth order effect or an infancy traumatized by premature birth and kidney problems.

“If he decides he wants to come out,” said Angela, “I’ll simply be the biggest advocate out there.”