Gender Is Not Just Chromosomes and Genitals

11 minute read

A 17-year-old recently walked into the office of Stephen Rosenthal, a pediatric specialist at UCSF Benioff Children’s Hospital in San Francisco. The high school student looked like a girl. She had external “girl parts.” She lived as a girl, dressed as a girl and had never had any question about being a girl. But her primary care doctor had become concerned because she hadn’t started developing breasts, something that happens to most girls by the age of 13. And a blood test the primary care doctor had given her revealed a clue as to why: this young woman had 46 XY chromosomes, the makeup usually associated with males. So off she went to Rosenthal, one of the nation’s leading experts on sex and gender.

This young woman, who has what is called an intersex trait, is not that rare. About 1 in 2000 babies are born with an uncommon permutation of the many things medical professionals typically look to—like anatomy, chromosomes and hormones—to establish a person’s physical sex. That’s the equivalent of about 10,000 babies born in the United States every year. For Rosenthal’s patient and her mother, this revelation was a source of great anxiety and insecurity. For everyone else, very private cases like hers are important examples to hear about and consider when lawmakers are attempting to decide who should use which bathrooms—as they have in legislation floated in states such as Arizona, Kentucky, Florida and Maryland in the last few years.

Most of those so called “bathroom bills” have failed, often after causing great controversy. But South Dakota is poised to become the first state to require that public school students use sex-segregated bathrooms and locker rooms based on their “chromosomes and anatomy as identified at birth.” That is the language in a bill that awaits a veto or signature from the governor and would affect an estimated 135,000 children in the state. Imagine the young woman in San Francisco lived there. Other children with intersex traits surely do. And then consider the reality of what such a bill could do to her life.

“So you would say every girl who goes into a bathroom has to not only pull down her pants and prove she has a vagina, but you also need to have a blood test and show you’ve got XX chromosomes?” says Rosenthal. “Well, that girl would have XY chromosomes. Which bathroom does she use?”

Other reasonable questions might include: is it the state’s place to be requiring revelations like the one she got in her doctor’s office? Given that most people never have their chromosomes checked, who in the state would pay for that? Would students have indications of whether they have a penis or vagina listed on their school records? While that all sounds absurd, how else could such a bill possibly be enforced, given that it implies one cannot simply take a kid’s or their parent’s word on which bathroom that child belongs in?


While the existence of intersex traits serves as a useful example of just how complicated sex and gender are—even if they seem obvious and simple to most of us—the debate about this bill has largely been about the effect it could have on transgender kids, those whose physical bodies don’t tend to align with their gender identity. And it should be. That’s what the bill is really about and whose bathroom use it is meant to control.

The legislation arrived after much controversy in the state over how schools should deal with transgender students who want to play sex-segregated team sports. And the bill states that if students do not want to use the bathroom or locker room that aligns with their anatomy and chromosomes, then they should use other accommodations—like a staff restroom or nurse’s restroom—which amounts to banning transgender girls from the girls’ rooms and transgender boys from the boys’. The bill’s design implies that the “true” identity of transgender kids must be revealed by testing their chromosomes and examining their bodies, because their sense of themselves is either not enough or nothing more than a costume.

You can’t throw a hall pass without hitting a medical professional or academic who will explain that sex and gender are distinct. “Sex is what’s between your legs and gender is what’s between your ears,” goes one quip. But even that is oversimplifying things, given that what’s “between your legs” could indicate that a person is male, while their chromosomes could indicate otherwise (a realization some 46-XX men come to after they’ve been having trouble having kids and they find out they have a low sperm count, leading their doctor to order chromosome tests).

The bill “assumes that there’s a clear-cut division between male and female,” says Elizabeth Reis, a professor of gender and bioethics at Macaulay Honors College, CUNY. “And that if we only dig hard enough we could truly distinguish between the boys and the girls. Throughout American history people have been trying to make these distinctions, and the reason why it doesn’t work is because those distinctions aren’t there. We don’t have any bright line.” Reis points to the sports world as an example, where officials have repeatedly drawn and then erased lines determining who is allowed to compete as a man or woman in the Olympics.


You could react to all this diversity by saying that anyone who falls outside the most typical combinations of these things is an aberration, in need of study or correction. But many people argue that we’re thinking about things the wrong waythat the reality of the world has never been a one-or-the-other situation like bathrooms tend to be. As Rosenthal points out, that’s the way we experience most human traits, so why should sex and gender be so different? We don’t go around being distinctly and uniformly smart or stupid, blonde or brunette, tall or short. Even if we do hover around averages, there are always exceptions to the rule.

A 2015 study published in the journal PNAS—entitled “Sex beyond the genitalia”—found that the majority of human brains are “mosaics.” Many features of the brain typically look one way in women and another in men, kind of like how, on average, men tend to be taller than women. It’s not an absolute indicator but looking at the features could, say, help a neuroscientist to make an educated guess about someone’s physical sex based on a scan of their brain. What the researchers found after analyzing MRIs of 1,400 brains was that most people have a mix of these features, some that look the way those features commonly do in males and others that look the way those features commonly do in females. “Brains,” the researchers concluded, “with features that are consistently at one end of the ‘maleness-femaleness’ continuum are rare.”

Though there’s no “gender gene” that’s been discovered, experts like Rosenthal say that there are clearly “biological underpinnings” to gender and that it “lives in the brain.” But, like there is more to sex than genitals, there is more to gender than a feeling in our brain that we have about ourselves. There is also the way that boys and girls are socialized to act, nurture interacting with nature. Then there is a person’s gender expression: whether they tend to act in ways that are thought of as masculine or feminine. Consider a butch woman who nonetheless identifies as a woman; she might be described as a person with a female gender identity and a more masculine gender expression.

Yet, says author, biologist and transgender woman Julia Serano, none of those is even the most important factor that affects one’s experience of gender on a day to day basis. That, she says, is “whether people perceive us as male or female and how they treat us.” And that assessment is usually made based another aspect of gender: secondary sex characteristics like having a beard or breasts and a person’s appearance, like whether they’re wearing a dress or whether their hair is short.

Those sex characteristics are largely the result of hormones, which is why, after they’ve sought hormone treatment, transgender men might grow bushy beards and start balding, while transgender women may grow breasts and experience a redistribution of muscle and fat that gives them more of an hourglass figure. These are the types of cues people are using to make determinations about other people’s gender, in mere seconds, untold times per day as we walk down the street. “If you’re happy with your gender,” says Serano, “you wouldn’t notice [people’s judgments about gender] as being this really important thing that comes into play all the time.”


Some critics of the South Dakota bill believe that the state should leave schools to handle bathroom questions independently, rather than legislating the issue—which will likely yield lawsuits. Several school districts have settled cases in which transgender students objected after being denied access to facilities or segregated from their peers. The Department of Justice has issued rulings that say barring transgender people from the bathroom that aligns with their gender identity is a form of sex discrimination, prohibited by Title IX. The Department of Education has issued similar guidance, indicating that kids’ gender identities should be respected. Federal courts are still weighing the issue, and a Virginia case will likely set an important precedent soon.

Other states have, meanwhile, gone in a more progressive direction. California passed its own controversial law, which social conservatives repeatedly tried and failed to repeal, which says that all students at public schools must be able to play on sports teams and use facilities that align with the gender identity, full stop. Critics of the South Dakota bill fall in line with that thinking, saying that the surest and most affirming factor to look to is where a child feels they belong. Forcing a transgender girl to use the boys’ locker room or a separate facility could, they say, lead to harassment, violence or ostracizing. “Lawmakers have been saying all along that these bills are put in place to protect our children,” says Ashley Joubert-Gaddis, the director of operations at South Dakota’s Center for Equality. “What these bills really do is single out children, they discriminate, and they’re making segregation okay.”

Joubert-Gaddis’ group is organizing a meeting on Tuesday with the Republican governor, Dennis Daugaard, so that he can meet some openly transgender people face-to-face—an experience he said in a recent press conference that he had never had. She and many others feel that bills and policies like the one being considered in South Dakota, which the transgender community views as discriminatory and harmful, are often the result of policy-makers simply not having a personal relationship with someone who experiences gender differently from the average Joe or Jane.

Decades ago, gay rights activists were on a mission to teach straight people that everyone has a sexual orientation—that it’s not that one is “natural” and one is “wrong” but that one is simply more common than another. Today, transgender rights activists are on a similar mission, explaining that everyone has a gender identity, which might be cisgender or trans* or something else entirely. “Our world is so binary, because it’s easier that way. It’s easier to be a Republican or a Democrat or gay or straight or transgender or cisgender, whatever,” says Rosenthal, who opposes the South Dakota bill. “It’s wonderful that … there are more and more people who are coming out and saying, ‘I am not on one end of the spectrum or the other.'”

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