How Many Genders Are There According To Science?

Gender identity has become a pressing topic of discussion and debate in recent years. With growing recognition of transgender, non-binary, and gender-nonconforming identities, the question arises – how many genders are there really, scientifically speaking?

If you’re short on time, here’s a quick answer to your question: While science does not provide an exact number, research suggests human gender identity and expression exist across a spectrum rather than discrete categories.

In this comprehensive article, we’ll explore what science reveals about the complexity of gender. We review research on biology, psychology, and sociology to understand how factors like genetics, hormones, brain structure, and social norms interact to produce a diversity of gender identities and expressions.

Sex Versus Gender

Defining the difference between sex and gender

Sex refers to the biological differences between males and females, such as chromosomes, hormones, internal and external sex organs. Gender refers to the socially constructed roles, behaviors, and identities of men, women and gender-diverse people.

Sex is typically categorized as male, female or intersex, while gender includes categories such as man, woman, transgender, genderqueer etc. While sex is biologically determined, gender is a social construct that can evolve over time as social norms and attitudes change.

Understanding the distinction between sex and gender is important, as a person’s sex does not always align with their gender.

Biological factors of sex determination

The biological factors that determine a person’s sex include:

  • Chromosomes: Females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY). Some intersex people may have other chromosomal combinations such as XXY.
  • Hormones: Testosterone and estrogen levels can influence biological sex characteristics.
  • Internal reproductive organs: Females have ovaries, fallopian tubes, uterus, cervix, vagina. Males have testes, vas deferens, prostate, seminal vesicles.
  • External genitalia: Females have vulva, clitoris, vaginal opening. Males have penis and scrotum.

These factors interact in complex ways to produce the phenotypic sex of an individual. However, biological sex exists across a spectrum and does not always fit neatly into binary categories.

Gender as social construct and identity

Unlike the biological determinism of sex, gender is largely socially constructed. Gender norms, roles and expressions vary greatly across different cultures and time periods. Some key aspects of gender include:

  • Gender identity: A person’s inner sense of being a man, woman, both or neither.
  • Gender expression: How a person presents their gender through appearance, clothing, behaviors and interests.
  • Gender roles: Societal expectations of how men and women should act, speak, dress, groom, walk, etc.

While gender may feel innate, it is also shaped by socialization from birth. An individual’s gender can fluctuate throughout life as they explore and understand their identity. There are limitless ways people can express their gender that may not align with traditional binaries.

Biological Factors Influencing Gender

Genetic and hormonal impacts

There are various biological factors that influence gender in humans. Genetically, the X and Y chromosomes determine sex at birth, with XY chromosomes producing males and XX chromosomes producing females.

However, hormones like testosterone and estrogen also shape physical characteristics and brain development in utero. For instance, those with XY chromosomes but complete androgen insensitivity will develop outwardly female bodies despite their genetic makeup.

This shows how genetics alone does not determine gender identity or presentation. Ultimately, there is a complex interplay between sex chromosomes, in utero hormone exposure, receptors, and how the body responds that affects biological gender development.

Brain structure and neuroscience

Emerging research on neuroscience and brain structure demonstrates certain differences between cisgender male and female brains. For example, some key areas like the insula are larger in cis women. However, there is considerable overlap between male and female brains, and large variation within the sexes.

Brain imaging studies of transgender individuals suggest their brain structure and responses align more closely with their gender identity rather than their biological sex. For instance, a 2017 study found certain regions in a trans man’s brain were similar to cis males, despite being assigned female at birth.

This provides evidence of biological factors underpinning gender identity.

Intersex conditions

There are a number of intersex conditions causing atypical sex chromosome configurations or disordered gonadal/genital development. For example, people with Klinefelter syndrome (XXY chromosomes) or congenital adrenal hyperplasia may not fit neatly into binary male or female categories, showing biology does not always align with a gender binary.

The existence of intersex individuals makes it difficult to claim human gender is strictly binary based on biological factors alone. Ultimately, there is a diversity of ways that genes, hormones, chromosomes, and sex characteristics can manifest in humans beyond just “male” and “female”.

The Psychology and Sociology of Gender

Understanding the psychology and sociology of gender is crucial in exploring the concept of how many genders exist according to science. This article will delve into three key areas: gender identity development, the social construction of gender norms, and gender expression across cultures.

Gender identity development

Gender identity development refers to the process through which individuals come to understand and define their own gender. According to scientific research, gender identity is not solely determined by biological sex, but rather a complex interplay of genetic, hormonal, and environmental factors.

The American Psychological Association (APA) states that gender identity is a deeply-held sense of being male, female, or something else, which may or may not align with the sex assigned at birth.

It is important to note that gender identity is distinct from sexual orientation. While sexual orientation refers to an individual’s emotional, romantic, or sexual attraction to others, gender identity pertains to how individuals perceive and experience their own gender.

Social construction of gender norms

The social construction of gender norms refers to the ways in which society assigns and enforces certain expectations, roles, and behaviors based on an individual’s perceived gender. These norms can vary across time, cultures, and societies.

For example, in some cultures, there may be more than two recognized genders, such as the hijra community in South Asia.

Gender norms are often reinforced through socialization, beginning in childhood. Children are exposed to societal expectations through their families, schools, media, and other social institutions. These expectations can shape their understanding of what it means to be a man or a woman, and can influence their behavior and self-perception.

Gender expression across cultures

Gender expression refers to the external manifestation of an individual’s gender identity, including their appearance, clothing, and behavior. It is important to recognize that gender expression is highly diverse and can vary greatly across different cultures and societies.

In some cultures, there may be more fluidity and acceptance of gender expression outside of the traditional binary of male and female. For example, the Two-Spirit concept among certain Indigenous cultures in North America recognizes and celebrates individuals who embody both masculine and feminine qualities.

Understanding the psychology and sociology of gender provides valuable insights into the complexity and diversity of gender identities and expressions. It is essential to approach the topic with an open mind and respect for the experiences of individuals across different cultures and communities.

The Gender Spectrum

Traditionally, society has recognized only two genders: male and female. However, scientific research and understanding of gender have evolved, leading to the recognition of a much broader spectrum of gender identities.

This recognition has given rise to the concept of the gender spectrum, which acknowledges that gender is not limited to a binary model but exists on a continuum.

Evidence for gender fluidity and non-binary genders

Scientific studies have provided evidence for the existence of gender fluidity and non-binary genders. These studies have shown that gender identity is not solely determined by biological sex, but rather a complex interplay of genetic, hormonal, and environmental factors.

For example, a study published in the journal Nature Communications found that certain variations in genes related to sex hormone receptors can influence gender identity. Moreover, research has also highlighted the existence of individuals who do not identify strictly as male or female but rather as genderqueer, genderfluid, or agender.

Limitations of male/female binary model

The male/female binary model, which categorizes individuals based on their biological sex, has come under scrutiny due to its limitations. This model fails to account for the experiences and identities of individuals who do not fit neatly into the categories of male or female.

It disregards the complexity and diversity of gender identities and can lead to marginalization and discrimination. Recognizing the limitations of this binary model is crucial for creating a more inclusive society that respects and acknowledges the diverse identities and experiences of individuals.

Different gender identity terms and classifications

As our understanding of gender expands, various terms and classifications have emerged to describe the diverse range of gender identities. Some of these terms include genderqueer, genderfluid, bigender, agender, and non-binary. Each term represents a unique experience and understanding of gender.

It is important to note that individuals may have different preferences when it comes to their gender identity and the terms they use to describe themselves. Respecting and using the preferred gender identity terms of individuals is essential for fostering inclusivity and acceptance.

Towards Gender Inclusivity

Importance of validating diverse gender identities

Science recognizes that gender is not limited to just two categories – male and female. Researchers and experts in the field have acknowledged that gender exists on a spectrum, with a wide range of identities beyond the binary.

This understanding is crucial for creating an inclusive and accepting society.

Gender inclusivity is important because it validates the experiences and identities of transgender and non-binary individuals. It acknowledges that their gender identity is valid and deserves recognition and respect.

By embracing the diversity of gender identities, we can break free from restrictive societal norms and promote a more inclusive and equal world for all.

Challenges still facing transgender and non-binary people

While progress has been made in recognizing diverse gender identities, transgender and non-binary individuals still face numerous challenges. Discrimination, stigma, and lack of understanding continue to hinder their full integration into society.

Transgender and non-binary individuals often face barriers in accessing healthcare, employment, and education. They experience higher rates of mental health issues and are more likely to be victims of violence.

These challenges highlight the urgent need for society to take action and provide support for gender minorities.

Actions society can take to support gender minorities

Creating a more inclusive society requires collective effort and action. Here are some steps that society can take to support gender minorities:

  • Educate oneself: Take the time to learn about different gender identities, terminology, and experiences. This will help foster understanding and empathy.
  • Advocate for legal protection: Support legislation that protects the rights of transgender and non-binary individuals. This includes laws against discrimination and gender-affirming healthcare access.
  • Amplify voices: Listen to and uplift the voices of transgender and non-binary individuals. This can be done through media representation, supporting their work, and creating safe spaces for dialogue.
  • Provide resources: Ensure that there are accessible resources and support systems in place for transgender and non-binary individuals. This includes healthcare providers, mental health services, and community organizations.

By taking these actions, society can work towards creating a more inclusive and accepting environment for gender minorities.

For more information on gender inclusivity, you may visit or Transgender Law Center.


While science has yet to pin down an exact number of genders, research shows human gender identity and expression exist on a multidimensional spectrum influenced by an interplay of biological, psychological, and social factors.

Increased recognition and acceptance of gender diversity will allow people of all gender identities to thrive as their authentic selves.

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