Gender: beyond the binary

Gender is one of the most fundamental — and at the same time most misunderstood — concepts of human experience. Often confused with biological sex, gender is actually a much broader and more complex concept, encompassing inner identity, the way we present ourselves to the world, and the expectations that society assigns to different categories. Understanding what gender is, how it differs from sex, how it has evolved historically, and what modern science tells us about it is essential for navigating the contemporary debate on identity, rights, and inclusion with awareness.

Gender and sex: a necessary distinction

The distinction between sex and gender is the starting point for any informed discussion on the subject. In everyday language, the two terms are often used as synonyms, but in scientific, medical, and psychological contexts they describe different realities.

What is biological sex

Biological sex refers to a set of physical and physiological characteristics: sex chromosomes (typically XX or XY), levels and types of sex hormones, internal and external reproductive anatomy, and secondary sexual characteristics. At birth, based on external genitalia, a sex is assigned — generally male or female. However, as highlighted by an article published in Nature in 2015, biological sex is not always reducible to a neat binary classification: intersex people, chromosomal variations, and atypical sexual development conditions demonstrate that biology, too, presents significant variability [12].

What is gender

Gender, according to the World Health Organization (WHO) definition, refers to the socially constructed characteristics of women, men, girls, and boys, including the norms, behaviors, and roles associated with being a woman, man, girl, or boy, as well as the relationships between these groups [1]. The WHO emphasizes that gender varies from society to society and can change over time [1].

The American Psychological Association (APA) adopts a complementary definition, describing gender as a multidimensional construct comprising gender identity (the inner sense of one’s own gender), gender expression (the way gender is communicated externally), and gender roles (social expectations linked to gender) [2]. According to the APA, gender is the result of the interaction between biological, psychological, social, and cultural factors [2].

In summary: sex concerns the body, gender concerns the overall experience — internal, relational, and social — of being a person in a world that ascribes meanings to the masculine and the feminine.

The three dimensions of gender

Gender is not a monolithic concept. It is articulated in at least three distinct dimensions, which can vary independently of one another.

Gender identity

Gender identity is the intimate and deep sense that every person has of their own gender: feeling like a man, a woman, a combination of both, neither, or something different. As recognized by the APA and the WHO, gender identity is a subjective experience that typically manifests in early childhood — between ages 2 and 4 — and may or may not correspond to the sex assigned at birth [2].

Neuroscientific research has demonstrated that gender identity has a significant biological component [10]. Twin studies have shown an estimated heritability index between 0.30 and 0.57, and neuroimaging research has shown that certain structural and functional brain characteristics of transgender people are more similar to those of cisgender people with the same gender identity [10]. Gender identity is therefore not a simple preference or a conscious choice, but a deep aspect of human experience with neurobiological roots.

Gender expression

Gender expression concerns the way a person communicates their gender to the outside world: clothing, hairstyle, body language, voice, the way they move through space. Gender expression can be described as more masculine, more feminine, androgynous, or any other combination.

A crucial aspect of gender expression is that it is largely shaped by cultural norms. What is considered “masculine” or “feminine” in clothing, demeanor, or behavior varies enormously across cultures and historical periods. High heels, today associated with femininity in Western culture, were worn by European aristocratic men in the 17th century. Pink, today often associated with girls, was considered a masculine color until the mid-20th century. These examples demonstrate that gender expression is not a direct reflection of biology, but the product of social conventions in constant evolution.

It is important to emphasize that a person’s gender expression does not necessarily correspond to their gender identity. A cisgender man can have a feminine gender expression without this calling his identity into question. Likewise, a transgender woman does not need to adopt a hyperfeminine gender expression for her identity to be valid.

Gender roles

Gender roles are the set of expectations, behaviors, and norms that a society assigns to people based on perceived gender. They include expectations regarding work, childcare, emotionality, aggression, leadership, and countless other areas of daily life.

Gender roles represent the most clearly social dimension of gender. As documented by anthropologist Margaret Mead in her pioneering study Sex and Temperament in Three Primitive Societies (1935), the traits considered “naturally” masculine or feminine vary radically across cultures [14]. Mead observed that among the Arapesh of New Guinea, both men and women behaved in ways that Western culture would have defined as “maternal,” while among the Mundugumor, both men and women were aggressive and competitive. Among the Tchambuli, gender roles were reversed compared to Western expectations: women were dominant and practical, men emotional and devoted to art [14].

These anthropological data, confirmed by decades of subsequent research, demonstrate that gender roles are not determined by biology but are the product of the social, economic, and cultural structures of each society.

A brief history of the concept of gender

The concept of gender as distinct from biological sex has a relatively recent history in Western culture, even though the realities it describes are as old as humanity.

Origins: from Simone de Beauvoir to John Money

The most famous phrase in the history of gender studies is probably that of Simone de Beauvoir in The Second Sex (1949): “One is not born, but rather becomes, a woman.” With this statement, de Beauvoir opened the way to the idea that femininity (and, by extension, masculinity) was not a natural given, but the product of a socialization process.

The term “gender” in its modern meaning was introduced in the scientific field by psychologist and sexologist John Money in the 1950s, to describe the behaviors and psychological characteristics associated with masculinity and femininity, distinguishing them from biological sex. Money proposed the concept of gender role to indicate everything a person does to reveal their condition as male or female.

Robert Stoller and gender identity

It was psychoanalyst Robert Stoller, in 1968, who introduced the concept of gender identity in his book Sex and Gender [5]. Stoller clearly distinguished sex — a biological fact — from gender — a psychological and cultural fact — and proposed that gender identity was the inner sense of belonging to a gender, independent of the physical characteristics of the body [5]. His work was fundamental for understanding the experience of transgender people.

The contribution of feminism and gender studies

Starting in the 1970s, the feminist movement adopted the sex-gender distinction as an analytical tool to unmask the naturalization of inequalities between men and women. If gender roles were not determined by biology but socially constructed, then they could be changed.

In 1987, sociologists Candace West and Don Zimmerman published the essay Doing Gender, in which they proposed that gender was not something one “is” but something one “does”: a set of everyday practices through which people produce and reproduce gender differences in social interactions [6].

Philosopher Judith Butler, with her book Gender Trouble (1990), pushed this analysis further, arguing that gender is performative: there is no pre-existing gender essence that is expressed, but gender itself is created through the repetition of acts, gestures, discourses, and bodily practices [4]. For Butler, even the distinction between sex and gender is problematic, since the way we understand and classify sex is itself influenced by gender categories [4].

Toward the current understanding

Over the past thirty years, the understanding of gender has been further enriched by contributions from neuroscience, genetics, and transgender studies. The current position of major scientific institutions — WHO, APA, WPATH — recognizes that gender is the product of a complex interaction between biological and social factors, and that gender identity has both neurobiological foundations and cultural dimensions [1][2][11].

Gender across world cultures

One of the most compelling pieces of evidence for the not exclusively biological nature of gender is the great variety of gender systems documented in human cultures. The male-female binary, while the most widespread system, is far from universal [13].

Two-Spirit people

In Indigenous North American cultures, Two-Spirit people (literally “two spirits”) have occupied a recognized and respected gender role for centuries, distinct from both masculinity and femininity. The term, adopted in 1990 at an intertribal conference in Winnipeg, replaces the earlier derogatory colonial terms. Anthropological research has documented over 150 precolonial North American Native communities that recognized gender roles outside the binary [13]. Two-Spirit people often held important functions in their communities as healers, spiritual guides, and mediators.

Hijra in the Asian subcontinent

The hijra in India, Pakistan, Bangladesh, and Nepal represent one of the oldest examples of a socially recognized third gender, with origins dating back to the sacred texts of Hinduism thousands of years ago [13]. In 2014, the Supreme Court of India officially recognized the hijra as a third gender, legally establishing a millennial social reality. Today, an estimated 500,000 to 2 million hijra people live in India.

Fa’afafine in Samoa

The fa’afafine (literally “in the manner of a woman”) are people assigned male at birth who in Samoan society assume traditionally feminine roles and behaviors [13]. The fa’afafine have been integrated and respected in Samoan culture for centuries, and their example demonstrates that gender diversity is not an invention of contemporary Western culture, but a recurring aspect of human social organization.

Muxe in Zapotec culture

In the Zapotec community of Juchitan de Zaragoza, Mexico, the muxe are people assigned male at birth who adopt feminine or intermediate roles [13]. The muxe are celebrated in the local culture and participate in an annual festival, the Vela de las Intrepidas, which honors their role in the community. The existence of the muxe demonstrates how a society can integrate gender diversity without marginalizing it.

Other cultures

Similar examples are found in many other societies around the world: the kathoey in Thailand, the quariwarmi in the pre-Columbian Andean tradition, the sworn virgins in Albania — women who assumed a masculine social role in a rigidly patriarchal society — and the bissu among the Bugis of Indonesia, where five distinct genders are recognized [13]. This cross-cultural recurrence across continents, eras, and profoundly different cultural traditions suggests that gender diversity is a constant trait of human experience.

What modern science says

The scientific understanding of gender has evolved significantly in recent decades, integrating evidence from psychology, neuroscience, genetics, and sociology.

Gender is not reducible to the brain

The study Sex beyond the genitalia: The human brain mosaic, published in PNAS in 2015 by neuroscientist Daphna Joel and colleagues, analyzed the brain scans of over 1,400 people, demonstrating that human brains cannot be classified into two distinct categories — “male” and “female” — but are rather unique mosaics of characteristics [7]. This result does not deny that statistical differences exist between groups, but demonstrates that at the individual level the brain is not sexually dimorphic in a clear-cut way.

Gender similarities

Psychologist Janet Shibley Hyde, with her Gender Similarities Hypothesis published in the American Psychologist in 2005, conducted a meta-analysis of 46 studies on psychological differences between men and women [8]. The result was that 78% of the measured gender differences were negligible or small in magnitude [8]. Men and women are psychologically much more similar than popular culture suggests, and the observed differences are largely the product of socialization, not biology.

Gender identity and neurobiology

While gender roles and expressions are largely socially constructed, gender identity has a documented biological component. A review published in the Journal of Neuroendocrinology in 2019 examined the neurobiological foundations of gender identity, concluding that genetic factors, prenatal hormone exposure, and brain development contribute to the formation of gender identity [10]. However, no single factor is deterministic: gender identity emerges from a complex interaction between biology and environment [10].

Positions of international institutions

The major scientific and health institutions converge in recognizing that gender is a spectrum and that identities outside the binary are natural variants of human experience.

The WHO defines gender as a social construct that varies across societies and over time, recognizing that the gender binary is a simplification that does not capture the full range of human experiences [1].

The APA, in its 2015 guidelines for psychological practice with transgender and gender non-conforming people, states that gender is a non-binary construct encompassing a broad spectrum of identities and experiences, and that transgender and non-binary identities are “normal variations of human gender expression” [3].

WPATH, in the Standards of Care version 8 (2022), explicitly recognizes the diversity of gender identities and for the first time dedicates a specific chapter to non-binary people, establishing the clinical recognition of identities outside the binary [11].

Gender in everyday life

Gender is not an abstract concept confined to textbooks: it is a force that shapes the daily life of every person, often in ways so pervasive as to be invisible.

Gender socialization

From birth — and sometimes even before, with gender reveal parties — people are immersed in a system of gender-related expectations. The color of the nursery, toys, clothes, the way adults talk to boys and girls, the sports activities encouraged: everything contributes to a process of gender socialization through which people learn what it means to be “male” or “female” in their culture.

This process is not neutral. Research has shown that unaware adults treat identical infants differently depending on whether they are told the baby is male or female: they speak more softly to the supposed females, encourage more physical activity with the supposed males. These differences, minimal at first, accumulate over time and contribute to creating the gender differences that are then perceived as “natural.”

Stereotypes and expectations

Gender stereotypes are rigid generalizations about the characteristics, behaviors, and roles appropriate for men and women. Some common examples: men “don’t cry,” women are “naturally” more empathetic, men are “suited” for mathematics, women for caregiving activities. These stereotypes, while sometimes containing a statistical kernel, have the effect of limiting the possibilities of all people — not only transgender or non-binary people — constraining them within rigid categories that do not reflect the complexity of individual experiences.

Gender as a social structure

Gender also functions as a social structure that organizes power relations, access to resources, and opportunities. Gender inequalities — in work, politics, the distribution of care work, violence — are not the inevitable product of biological differences, but the result of social systems that attribute different value and power to different gender positions. Understanding gender as a social construction does not mean denying its reality, but recognizing that its specific forms are the product of collective choices and, as such, can be transformed.

Beyond the binary: the gender spectrum

The conception of gender as a spectrum, rather than as a rigid binary system, is today supported both by scientific research and by the experience of millions of people around the world.

Non-binary people — those whose gender identity does not fall exclusively within the category of man or woman — represent an increasingly visible and documented reality [9]. Recent surveys suggest that about 1-2% of the adult population identifies as non-binary, with higher percentages among young people. Under the umbrella term “non-binary” are gathered diverse experiences: genderfluid people, whose gender identity changes over time; agender people, who do not identify with any gender; bigender people, who identify with two genders; and many other identity configurations.

Recognizing the gender spectrum does not mean abolishing the categories of man and woman, which remain meaningful for the vast majority of people. It means rather recognizing that these categories do not exhaust the full range of human experiences, and that people who fall outside the binary deserve the same respect and recognition.

Why gender matters

Understanding gender is important for several reasons that go beyond academic debate.

First, an accurate understanding of gender is essential for the health and well-being of transgender and non-binary people. Research shows that the psychological distress experienced by many transgender people is not caused by their gender identity, but by stigma, discrimination, and lack of social recognition. Understanding that gender is a spectrum and that non-conforming identities are natural variants of human experience helps reduce this stigma.

Second, understanding gender helps all people — not only transgender people — to recognize and challenge the stereotypes that limit their possibilities. A boy who loves dance, a girl passionate about mechanics, a father who chooses to devote himself to childcare: all of these people benefit from a society that does not impose rigid roles based on gender.

Finally, understanding gender is a prerequisite for building a more just society. Gender inequalities — from the wage gap to gender-based violence, from political underrepresentation to the inequitable distribution of care work — cannot be addressed without understanding the mechanisms through which gender is constructed, reproduced, and naturalized.

Gender is a complex reality that spans biology, psychology, culture, and social structure. It is reducible neither to the body nor to society, but emerges from the interaction between these dimensions. Recognizing this complexity is not an ideological act, but an act of understanding — of science, of history, and, ultimately, of the irreducible variety of human experience.