Sex vs. Gender: Definitions, Differences, Expression, and Identity

Medically Reviewed By Emelia Arquilla, DO

“Sex” and “gender” have different meanings. Sex refers to biological features, while gender refers to personal and social expression. Often, people use the terms “sex” and “gender” interchangeably. However, the words do not always match in a way that traditionally aligns with U.S. or Western ideas.

This article explains sex vs. gender and how they differ. It also discusses identity and expression and answers some frequently asked questions.

What is sex?

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Sex refers to your biological and anatomical characteristics. This can include your:

  • reproductive organs and genitals
  • hormone levels
  • chromosomes

Based on these characteristics, you were likely assigned a sex at birth by a doctor. In some Western cultures, this has historically involved being assigned a sex from one of only two categories: female or male. This is known as a binary — it has two options.

For example, you may have been assigned female if you have ovaries and XX chromosomes or male if you have testes and XY chromosomes.

However, some people have a mix of characteristics that are not exclusively male or female. Some people are born intersex, which is also known as having differences in sexual development (DSD). 

Differences in sexual development (DSD)

Having DSD means that a person is born with anatomy that does not exclusively fall within the male or female category. A person may have:

  • some ovarian tissues and testicular tissues
  • combinations of XX and XY chromosomes, such as XXY chromosomes
  • external genitals that typically fall into one female or male category, with internal genitals that fall into the other category
  • differences in genitals, such as a scrotum that is empty or resembles labia

Clinicians may sometimes see DSD at birth based on external features. In other cases, it may not be apparent that you have DSD based solely on external appearance.

This can occur when your genitals do not match your internal reproductive organs. In such cases, you may not discover that you have DSD until later in life, such as during puberty, or you may never know.

Having DSD is a natural feature in humans and isn’t a disease. It doesn’t necessarily need medical treatment.

Around 1–2 out of every 100 people born in the United States may be intersex.

What is gender?

Unlike sex, gender is not based on biological or anatomical features. Gender refers to personal and social expressions, identities, and roles. Gender also includes how these features relate to being a woman, a man, or having another identity.

Binary ideas have traditionally been used to define gender in the United States, based on the belief that gender is always the same as a person’s sex. This includes recognizing only two genders, woman or man.

However, gender is a social construct. Ideas and standards of gender have been created Trusted Source World Health Organization Highly respected international organization Go to source by different social groups and can vary widely by different societies.

Many societies Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source and cultures have used nonbinary definitions of gender for a long time. Ideas of gender are also not fixed on biological features and can vary with culture and change throughout time. For example, some Native American people recognize a third gender known as “two-spirit.”

In a 2016 review in the International Review of Psychiatry, researchers suggest that gender may consist of a broader spectrum and not only the typical ideas of sex and man or woman. Some people’s gender identity differs from their sex.

Gender expression and identity

Gender can also vary across personal identity and expression.

Gender identity

Gender identity refers to your sense of self. It may not always match your sex in a way that aligns with traditional ideas in the U.S.

A person who has a gender that does not traditionally correspond to sex may be referred to using the following terms, depending on their specific identity:

  • transgender
  • gender nonconforming
  • genderqueer
  • nonbinary

For example, a person who identifies as a man and was assigned female at birth may be transgender. Someone who does not identify with either binary gender of man or woman may be nonbinary. However, there are other terms to describe gender that people may use.

Also, a person who has a gender that corresponds with their biological sex in a traditional way can be referred to as “cisgender.” For example, a person who identifies as a man and was assigned male at birth is cisgender.

As a result, your gender identity is personal and may not necessarily be outwardly visible to those around you.

Gender expression 

Unlike gender identity, your gender expression is visible to those around you. It is an external representation of gender and can be influenced by many personal factors.

Gender expression can include your behaviors and outward appearance, such as:

  • how you dress and style yourself
  • your body language
  • your mannerisms
  • your pronouns
  • your chosen name

These characteristics may not always align with social or stereotypical expectations.

Like gender identity, gender expression exists on a spectrum. People may express themselves as masculine, feminine, androgynous, nonbinary, or a combination that they feel fits.

Also, gender expression is sometimes related to gender identity but not always. For example, a person may style themselves traditionally femininely but identify as a man. Another person assigned male at birth may identify as a woman but present as a man for fear of how others or society will act toward them.

FAQ

Emelia “Mimi” Arquilla, D.O., has also reviewed the following frequently asked questions.

Who made the difference between sex and gender?

Sex and gender have been different concepts in many cultures for a long time. No one person or culture has created a difference between sex and gender.

However, understanding and definitions of sex vs. gender are still developing in the U.S.

Are there only two sexes in humans?

Some Western and conventional medical cultures, such as those in the U.S., had recognized only two sexes: male and female.

However, researchers are now acknowledging additional sexes. This can include when people are intersex and have features that do not correspond to just one male or female category. This is also known as having differences in sexual development.

How many genders are there?

The number of gender identities may be endless. This is because:

  • gender is a spectrum — there are many gender identities, and they cannot be categorized into just man or woman
  • gender identity can be unique to each person
  • gender is a social construct — it’s not fixed on biology but instead can vary per culture and belief

Summary

Some social groups, including some people in the U.S., believe that sex and gender refer to the same concept. However, sex and gender have key differences.

Sex refers to a person’s biological and anatomical features, including chromosomes, hormone levels, and reproductive organs.

Gender refers to personal and social expressions, identities, and roles related to being a woman, man, or another gender identity. While sex can be biological, gender is a social construct that can vary based on personal and cultural ideas.

Discussing sex and gender is not always simple, as both exist on spectrums and can vary. However, respecting each person’s differences and identities regarding their sex and gender matters.

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Medical Reviewer: Emelia Arquilla, DO
Last Review Date: 2023 Apr 5
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