The XX & XY Lie: Our Social Construction of a Sex and Gender Binary

When a scientific system misses millions of people, is the problem with the people who don’t fit or the system itself?

Sara C
21 min readOct 21, 2017
Image credit: Petite Bohème at
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For additional perspectives on trans identities, trans bodies, and the intersection of trans identities and white colonialism, I recommend Tiq Milan (here as well), Alok Vaid-Menon, DarkMatter, Kai Cheng Thom, Zachary Pullin (Chippewa Cree), Gwen Benaway and more indigenous authors and organizations listed here. I am writing this article from the perspective of a white trans woman because it’s informed by my own experience of intersectional race and gender.

I’m a transgender woman. Like many trans people I know, I’ve spent a lot of time in my life hearing from friends, family, and strangers on the internet about how my gender is “made up”.

These detractors always circle back to the same argument regarding biology, genitals, and the existence of only two “real” genders. They will tell me that it doesn’t matter what name I use, how long my hair grows, what surgeries I get, or how long I take hormone replacement therapy, I will always be a man, in their eyes, because one doctor 27 years ago looked at my penis and decided I was a man.

This simplistic explanation of sex and gender as a permanent division between someone being either a man or woman, having a penis or a vagina, and having XX or XY chromosomes may seem like solid ground upon which we’ve built our entire modern society, but the real story of where these categories come from, and how unscientific they truly are, is newer, and much more cloudy, than you may think. Before we go down the rabbit hole, we need to cover some basics first.

Social Constructionism and You

Social constructionism is the study of how identity categories, social groups, and even things that seem like solid biological truths, are actually systems of meaning that are built, maintained, and obscured from criticism by our social systems.

Social constructionism is created and maintained by many facets of society, including our education system, class hierarchy structure, political systems, and medical complex. (More about social constructionism here:

It’s important to note that just because something is socially constructed, or in a more blunt way, that it is “made up”, doesn’t make that thing meaningless or powerless. Money only exists and has value because we all collectively decide to continue believing that it has value, however once that social construction has taken hold, it becomes “real” in some sense of the word. The fact that money is an imaginary abstraction of labor and personal wealth onto colored pieces of fabric, paper, or metal doesn’t make its impact on our lives, or our struggle to live without having enough of it, any less “real” than something tangible like a rock or a tree.

As another example, racial divisions between human beings with different skin tones and body features are socially constructed and yet, also deeply important to understanding our world. These divisions were artificially created and continue to be maintained by white-dominant societies across the world in a way that produces real, daily harm for people of color.

Even though race is “made up”, so to speak, we can’t just completely dismiss it as a concept, or live in a “colorblind” society because the enduring legacy and impact of race as a social construction impacts the lives of every person of color. It is deeply important for us all to learn about the challenges of growing up in a society informed by slavery, scientific justifications for racism, eugenics, and many other real systems of oppression that were built on the very non-real and arbitrary divisions between humans of different physical appearances. In order to truly confront the issue of racism, we must first admit that race is both a social construction by scientific racists and also a real pattern of classification that has caused tangible harm despite it being “made up”.

In a similar way, our current system of assigning babies male or female at birth is a social construction based on assumptions about biology and body development that are now outdated. However, we must still grapple with the centuries of meaning we have attributed to the penis and the vagina.

Sex and gender as a binary structure are outdated social constructs that we must reform. When a so-called “scientific” system of categorization systematically leaves out millions of transgender and intersex people, we must ask ourselves: is the problem with the people who don’t fit, or the system itself?

Boys and Girls

In most current societies, when we’re born, a doctor or midwife looks at our genitals and declares we are either “a boy” or “a girl”.

This designation gets put on a birth certificate, which then transfers to a social security card, a driver’s license, a passport, and every other possible documentation of you as a human being. Even though most people never get their chromosomes tested, we also assume this sex assignment to mean that people with penises always have XY chromosomes and people with vulvas always have XX chromosomes.

We live in a world that is deeply invested financially, socially, politically, and scientifically, in reinforcing two categories defined by penises and vaginas. The sex and gender binary informs our medical research, divides our restrooms from each other, and prescribes everything from the hobbies you can access to the style of draping cloth on your body that is appropriate.

Our binary division of genitals, loosely based on being able to give birth or not give birth, signifies a fundamental difference between what we call “men” and “women”. From the assignment of your physical sex follows the assumption of your gender identity and gender expression to match.

If your gender happens to line up with the sex you were assigned at birth, this is an experience I will refer to as being “cisgender”. Conversely, this means that anyone whose gender is not the same as their sex assigned at birth would be “transgender”.

Cisgender people may have never really thought much about the medical process of sex assignment at birth and the subsequent social process of molding the expectations of a gender identity based on that assignment.

Even though sex assignment at birth, gender identity, and gender expression are all distinct categories that can be independent from each other, when they all “line up” with the expectation, we collapse those three things into one identity. We call someone a “man” for example, by which we actually mean a male-assigned-at-birth person whose gender identity (internal sense of gender) is a man, and whose gender expression (external choices about appearance to communicate gender) is also male/masculine.

Even though no one truly lines up with every expectation of being male or female, odds are that if you fit into a cisgender experience of your body and the world, our cultural process of assigning sex at birth and then assuming a gender identity and gender expression based on that assignment has been an invisible process for you. It may even feel like a “natural” process, or the only process by which we could ever structure our society in your mind.

For cisgender people, this medical process of assigning sex at birth and assuming gender identity and expression from that assignment is like tubing down a river. Depending on where you start, you may experience calm waters carrying you forward, you may have turbulent water that’s difficult to navigate, or you might have a mixture of both, but no matter what, the momentum of the water carries you forward and helps guide your journey.

For transgender people, whose gender is different from the sex we were assigned at birth, and intersex people, whose bodies do not fit cleanly into being assigned male or female, this experience is much more like being a salmon swimming upstream against the current. Even though it’s possible to do, it’s exhausting. We’re always pushing back against the expectations of our culture, our parents, our doctors, our religious leaders (if we’re religious), and practically everyone we interact with in person and on the internet.

Some of us don’t survive the journey. Some of us run out of energy and fall behind. Some of us, if we’re non-white, poor, queer, non-binary, living with a disability, living in countries outside of the US and Europe, living without access to healthcare, or navigating life through multiple marginalized identities at once, are forced to endure push back from the unstoppable flow of dominant culture that is more intense, more relentless, and much more exhausting.

This social process of “tubing down the river”, happens because of our social construction of the gender binary. While not everything in our modern society has a binary gendered aspect to it, many more things than you might think about actually do.

The gender binary is more than social expectations that women work in the home and men work in an office, or other broad cultural assumptions about men and women. Our gendered divisions assign different smells to different genders, make sure that our underwear is shaped differently, and use social norms about grooming activities like shaving body hair, doing makeup, and enforcing drastically different dress codes all serve to support divisions between what we call men and women.

We take small variations in body structure and amplify the natural variation of those bodies to maintain the idea that men and woman are not only fundamentally different from each other, based on their biology, but also based on their social expectations as well.

More and more people are beginning to see how our current gender binary is socially constructed. Parents are beginning to push back on the idea that only certain toys are for boys or girls, clothing stores are removing their distinction between men’s and women’s clothes, and California just became the first state in the US to recognize a non-binary gender on their state records.

Even though it’s becoming more common to hear people discuss the impact of our gender binary, we still seem to struggle when we apply the same ideas to the social construction of biological sex itself.

“I Wasn’t Born In The Wrong Body, I Was Born In The Wrong World” — Alok Vaid-Menon

Even the most progressive transgender allies, the ones who understand the nuances of gender identity, can struggle with the concept of trans bodies when it comes to the social construction of physical sex characteristics.

Many cisgender allies say things to me like: “I support your transition, but you’ll never be a ‘real’ woman because you were born a boy.” Statements like this illustrate how some people can understand our society’s need to expand beyond the gender binary, while still clinging to the idea that “biological sex” is something solid, real, and based on a purely biological difference between two types of genitals and having either XX or XY chromosomes.

Not only is the gender binary a social construction, but so is the very idea of a physical sex binary at all. We know this because millions of transgender people exist as women in bodies with penises, as do men in bodies with vulvas and nonbinary people in bodies with any genitals.

Those bodies cannot be cleanly sorted into a binary sex because our brain is just as physical a part of us as any other. We experience our whole body through electric energy that runs through every nerve and up into our brain seamlessly.

There is no such thing as being trapped in the “wrong” body, it’s the only body I have, and to say it isn’t a woman’s body when there is a woman living in the body takes some serious mental gymnastics and biological psuedo-science for people to justify their transphobia and declare otherwise.

Bigots and allies alike search high and low for every possible explanation to elucidate why millions of trans people exist, other than what we keep saying over and over again.

This world seemingly refuses to listen to trans people when we say that we are simply living as our truest possible selves. We are women, men, and non-binary people in bodies that you refuse to see as ours, but rather, you can only see through your projections onto us.

Transgender women are not “trying to be women”, “living as women”, “becoming women”, “choosing to be women”, or any other euphemistic phrase that essentially says we are impersonators trying to be something we are not.

As Sophie Labelle so elegantly put it: “I’m a girl, this is my body. Girls have all kinds of bodies.”

Artist credit: Sophie Labelle, Assigned Male Comics

Additionally, some bodies cannot be cleanly sorted into “male” or “female” on sex assignment, and we categorize those bodies as “intersex”.

Intersex folks may or may not also identify themselves as “transgender”, but the existence of bodies that are on a spectrum between what we clearly define as male or female speaks to a more complicated truth of “biological sex” than you might have learned in school.

Even though we often think about physical sex being determined precisely when the sperm enters the egg, the actual development of our physical bodies follows the same template for the first few months of development, including the development of budding structures that would become the ovaries, labia, clitoris, and other body parts we currently see as exclusively “female”.

For some bodies where the SRY gene is activated, these existing parts transform themselves to a new genital configuration that will begin to produce testosterone. The ovaries descend and become the testes; the labia fuse together into the scrotal sack; the urethra fuses with the clitoris and grows out to become the penis.

The anatomy we see as distinctly “male” or “female” is all grown from the same root, and in our effort to make clear distinctions between men and women, the medical system creates collateral damage through forced genital surgery on intersex infants, defining our natural human variation as a disorder, and perpetuating a transphobic medical gatekeeping process that construes our most basic medical care as “cosmetic” and “unnecessary” medical procedures we must pay for out of pocket, while trans people are also twice as likely to be unemployed, and if employed, are twice as likely to make under $25,000 a year (from:

Even though we claim this division between “real men” and “real women” rests on the basic difference between XX and XY chromosomes, even the clean cut science of that divide is quickly becoming more and more muddled. It is possible, for example, to have XY chromosomes and a vulva or XX chromosomes and a penis. This article from Nature Magazine in 2015 outlines this process in greater detail:

“Gene mutations affecting gonad development can result in a person with XY chromosomes developing typically female characteristics, whereas alterations in hormone signalling can cause XX individuals to develop along male lines.

For many years, scientists believed that female development was the default programme, and that male development was actively switched on by the presence of a particular gene on the Y chromosome. In 1990, researchers made headlines when they uncovered the identity of this gene, which they called SRY. Just by itself, this gene can switch the gonad from ovarian to testicular development. For example, XX individuals who carry a fragment of the Y chromosome that contains SRY develop as males.”

By the turn of the millennium, however, the idea of femaleness being a passive default option had been toppled by the discovery of genes that actively promote ovarian development and suppress the testicular programme — such as one called WNT4. XY individuals with extra copies of this gene can develop atypical genitals and gonads, and a rudimentary uterus and Fallopian tubes. In 2011, researchers showed that if another key ovarian gene, RSPO1, is not working normally, it causes XX people to develop an ovotestis — a gonad with areas of both ovarian and testicular development.

These discoveries have pointed to a complex process of sex determination, in which the identity of the gonad emerges from a contest between two opposing networks of gene activity. Changes in the activity or amounts of molecules (such as WNT4) in the networks can tip the balance towards or away from the sex seemingly spelled out by the chromosomes. “It has been, in a sense, a philosophical change in our way of looking at sex; that it’s a balance,” says Eric Vilain, a clinician and the director of the Center for Gender-Based Biology at the University of California, Los Angeles. “It’s more of a systems-biology view of the world of sex.”

Transgender people are a natural human variation of brains existing on a spectrum of identities, just like how bodies exist on a spectrum between what we designate as male and what we designate as female.

Both the gender binary and the sex binary are socially constructed. We first decided there was a difference at all in bodies on one side of the sex spectrum or the other, and then we maintain a system of strict division between physical norms, social norms, and gender expression norms that reinforce that original arbitrary division between masculine and feminine bodies.

We are led to believe that this “biological” division between men and women is tied to both the genitals, and having XX or XY chromosomes, however, most people never have their chromosomes checked. Instead, we just assume that the existence of a penis means someone has an XY chromosomal pair and the existence of a vulva means an XX chromosomal pair. But as we saw above, not only can someone be born with the “wrong” genitals for their chromosome pair, but also those with the “right pair” of chromosomes can develop traits of both genitals, including the full formation of both a penis and a vulva/vagina at the same time.

This doesn’t mean there aren’t observable differences between bodies, or that a division does exist in humans between the anatomy required to grow a child and those without the ability to do that, but it does mean that the actual biological differences between those bodies stops there. Even using birth anatomy as a binary doesn’t work, since we still see infertile cisgender women as women and infertile cisgender men as men.

Imagine a thought experiment: Due to an unfortunate accident, you were crushed above your hips by a massive object. In order to save you, the surgeon was required to remove your genitals completely. Do you stop being a man or a woman, in this scenario, just because your genitals are now gone? Of course not, because gender, the inner sense of who you are, exists independent of your genitals.

Instead of thinking about physical sex as two distinct categories with no overlap, I think it makes more sense to think of our categories of “male” and “female” as two bell curves centered around cisgender men and women. The majority of people who are born with a penis will identify as men, express themselves as masculine, and create the norm we have now, and the same for people with a vulva being women and expressing themselves as feminine.

However, there is a small chance on the edges of the bell curve that someone will be different from how they are assigned and expected to grow up. They may be a transgender woman, agender, gender fluid, or many other potential identity terms we’ve created to describe experiences outside of being cisgender. That doesn’t make the transgender or the cisgender person more or less right, just because it’s more common to be cis, it just means they are two very different experiences of being human.

Instead of seeing this natural variation within the bell curve as equally valid outcomes of the randomness inherent in human genes, we have medicalized, stigmatized, and pathologized these differences to say that less common experiences of gender are also somehow less “right” or less “natural”.

We’ve labeled these trans experiences as deviant, dangerous, and constructed them to be something wrong with the individual people, instead of an inherent flaw of our classification system.

If a so-called “scientific” classification system continues to systematically leave out millions and millions of people, we must ask ourselves: is the problem with those millions of people, or is the problem with our current classification system?

When the majority of people fit within the expectations of being cisgender men and women, we mistake something “common” for being something “normal”. In our current society, “normal” comes with all sorts of value judgements and safety systems that push us toward wanting to be seen as “normal” by others.

Additionally, having a category seen as “normal” for our gender fundamentally facilitates the creation of things outside of those expectations to be seen as “not normal”, or“other”. Our experiences precede our language to describe them. Trans and queer people who are naming terms to describe their gender are putting language to experiences of gender fluidity, non-binary gender, and other experiences outside of the historical categories of men and women.

Getting rid of those new identities, marginalizing them, mocking them, and ignoring them don’t make someone feel less like that identity, it just increases the social cost of coming out and staying out to a level where someone may feel hopeless enough to choose dying instead.

Our society constructs these transgender identities as being “abnormal”, “bizarre”, and defined by their defiance to the established norm.

Those who are hateful of trans people do all sorts of mental gymnastics to find other explanations for why trans people exist. These “explanations” are often way more complicated than the actual truth they refuse to acknowledge, that I am simply a woman who has a penis.

Instead, transphobic bigots justify taking our rights away and ostracizing us from society by saying that transgender people are sexually deviant, or that we are trying to trick people. They call our truest selves being “mentally ill”, and all sorts of other justifications for marginalizing and oppressing us without feeling guilt or shame for it. The people who truly cause harm to us are often telling a story in their own head about “saving us” from ourselves, but all they are really doing is using religious fundamentalism, TERF ideology, or other oppressive systems to attack an already endangered and marginalized group and endanger us further out of their own discomfort and fear.

Binary Sex and Gender Come From Colonialism, Not Nature

It is also important to note that even though trans identities and gender fluidity seems like something new, there is a long history of people who we would understand in our current context as “trans” throughout time and space. Many Civil War soldiers were discovered to be female assigned at birth in the US, Billy Tipton was a legendary jazz artist, who was also discovered to be female-assigned-at-birth only upon his death in 1989. There were also trans, genderqueer and gender fluid people living in a burgeoning queer movement in 1920’s and 30’s Berlin, until the Nazis came to power, destroyed the collected research of Dr. Magnus Hirshfeld, and the entire queer movement toward scientific understanding with it.

Trans women, transsexuals, and drag queens of color were also the first ones to fight back against police at Stonewall in June 1969, and also at the Compton Cafeteria Riots, in August 1966, almost 3 years before Stonewall.

Additionally, going back further than white European colonialism, there have always been communities of indigenous people who saw and respected people outside of a gender binary. While it’s impossible to paint the hundreds of indigenous groups in North America with a broad brush, many different traditions of indigenous gender and sexual fluidity are being illuminated by current tribal members, sometimes under the linguistic banner of “two spirit” people:

“Each tribe has their own specific term, but there was a need for a universal term that the general population could understand. The Navajo refer to Two Spirits as Nádleehí (one who is transformed), among the Lakota is Winkté (indicative of a male who has a compulsion to behave as a female), Niizh Manidoowag (two spirit) in Ojibwe, Hemaneh (half man, half woman) in Cheyenne, to name a few.

As the purpose of ‘Two Spirit’ is to be used as a universal term in the English language, it is not always translatable with the same meaning in Native languages. For example, in the Iroquois Cherokee language, there is no way to translate the term, but the Cherokee do have gender variance terms for ‘women who feel like men’ and vice versa.”

Many of the colonial occupiers that traveled to North America were not only confused by sex and gender categories different from their own, but they used their lack of nuclear families and existence of trans and queer people as a sign of godlessness and weakness, as the same article continues below:

“The Jesuits and French explorers told stories of Native American men who had ‘Given to sin’ and ‘Hunting Women’ with wives, and later, the British returned to England with similar accounts. [portrait artist] George Catlin said that the Two Spirit tradition among Native Americans ‘Must be extinguished before it can be more fully recorded.’ In keeping with European prejudices held against Natives, the Spanish Catholic monks destroyed most of the Aztec codices to eradicate traditional Native beliefs and history, including those that told of the Two Spirit tradition.

In 1530, the Spanish explorer Cabeza de Vaca wrote in his diary of seeing ‘soft’ Native Indian males in Florida tribes dressing and working as women. Just as with all other aspects of the European regard for Indians, gender variance was not tolerated. Europeans and eventually Euro-Americans demanded all people conform to their prescribed two gender roles.

The majority of historical empires and colonizing powers across the world have been based on a combination of heterosexuality and a binary sex assigned at birth, partially because if you are a colonizing power that needs new people to be born in order to constantly grow your army and occupy your new territory, then creating shame and stigmatization around any sex that is non-procreative and punishing people for stepping outside of gender norms becomes a social adaptation that allows empires to grow through the assumption that all people must be straight and wanting to have children.

We are beyond a time when these desires need to be the sole focus of a society. When people fall in love and/or have sex with genitals where a child can be born, great! And also there are many more options existing in this world to create your own children with another person, or grow your family by adopting those who don’t have one.

When we create a system of strict gender policing and threats of violence, sexual assault, homelessness, and more for crossing those boundaries, it’s hard to say the choice to stay within them is a “natural” one.

To Infinity And Beyond

Our ever-expanding scientific, social, and cultural understanding of the world is pointing more and more to the system of a gender and sex binary being unable to describe the natural human variation that has always existed in gender and sex, and which will likely always exist, no matter how many times an internet comment is written that there are only two genders, only two sexes, and only one way to see the world.

Bodies exist on a spectrum just as our brains and identities do. There is no clear distinction between a man and a woman, no matter how many non-consensual genital surgeries we perform on intersex infants. In order to make it appear that there is a stark difference between these two, we enforce clothing standards, body hair standards, makeup expectations, and genital surgeries on intersex people to make the actual differences that do exist between those body types hyper-emphasized and seemingly impossible to mix.

However, it is possible to have XY chromosomes and a vulva. It is possible to have XX chromosomes and a penis. It is possible to be born with both a penis and a womb. It’s possible to be born with both a penis and a vagina. It is, therefore impossible for us to truly create a divide between “man” and “woman” as distinct categories, especially if we plan to use chromosomes and genitals to divide them. Nature doesn’t like cleanly divided categories.

There are certainly biological differences between bodies, and some of those differences can be traced back to different body parts, some of those differences may even lead to some differences in thought, experience, and interests, however we know better than to say that such a random cluster of similarities are so important that they are more important than allowing trans and queer people to live freely and safely as we feel the most comfortable in our bodies.

I believe we should consider alternatives like remaking our sex assignment system, and all of the connected documents and expectations, to be held by a gender neutral placeholder until the person can communicate their gender and sex clearly instead of creating years, and potentially decades, of collateral damage by assigning someone incorrectly at birth. We can no longer claim that having one set of genitals puts you automatically into any one social category of gender or biological sex.

Instead of letting our genitals define our gender, the more accurate thing to do is allow our gender to define our genitals. If you’re a cisgender man with a penis, no one is saying you shouldn’t identify that way or that it’s wrong, simply that we need to have a classification system that is granular enough to include cisgender men with penises, women with penises, and non-binary people with penises, vaginas, or both as well.

Despite being born with a penis, I am not a “woman with male genitalia” or a “woman trapped in a man’s body”, both of which are ways to acknowledge the existence of transgender women without actually validating our identity as women. As I said in my previous piece, trans liberation is very simple, as long as we hold this to be true: “Trans women are women. Trans men are men. Non-binary people are whole and valid identities outside of our western colonialist sex and gender binary. Repeat this to yourself over and over. This is the root of all trans liberation.”

I am a woman, so I have a woman’s body. My penis is a woman’s penis. My voice is a woman’s deep voice. My body hair is a woman’s body hair. Sex assignment at birth based on a genital inspection is nothing more than a social construction that takes the complicated bodily experience of humans and reduces it into just two categories.

The gender binary and the physical sex binary are both made up and real at the same time, they are constructed by human beings, but that doesn’t mean they aren’t important or impactful to everyone. Being a social construction means that we, as human beings, made this system and maintain this system. And if we made this system, it also means that we can remake this system to include the wide, natural variation of all human bodies and minds.

Sara is the host of the Queer Sex Ed Podcast. You can learn more about her work and listen to the show at or on any podcast app. You can also follow QSE on Facebook at and on Twitter @QSEpodcast. If this article has enriched your life, and you would like to support the continuing work of QSE to educate and create queer, intersectional spaces for conversations about sex and sexuality, please consider joining our Patreon community at

This piece pulls heavily from knowledge gained here, here, and here



Sara C

Educator, author, and queer trans woman. Co-host of the Queer Sex Ed Podcast. More about QSE: Support my work: