Many people use the two terms as if they mean the same thing. News reports, forms, and everyday conversation often blend them into one acronym. Yet sexual orientation and gender identity describe two very different parts of a person. Health organizations, psychology bodies, and human rights institutions all treat them as separate dimensions of human experience [1, 2].
This guide explains each concept in simple words, shows how they differ, reviews what current research says, and separates documented facts from common myths.
The short answer
Sexual orientation is about who you are attracted to. Gender identity is about who you are. One points outward, toward other people. The other points inward, toward your own sense of self. Crucially, one does not predict the other. A person’s gender identity tells you nothing reliable about their sexual orientation, and vice versa [1, 2].
What is sexual orientation?
Sexual orientation refers to the sex of the people to whom a person is sexually and romantically attracted [2, 3]. It is commonly described with labels such as heterosexual (straight), lesbian, gay, or bisexual. Other labels people use include queer, pansexual, and asexual, which describes a person who experiences little or no sexual attraction [2].
Sexual orientation is broader than behavior alone. It can include attraction, feelings, fantasies, behavior, and the identity label a person chooses. These usually line up, but not always [4]. Research also shows that orientation does not always fit neat boxes. It can exist on a continuum, and for some people, especially some women, it can shift over time [2, 3].
What is gender identity?
Gender identity is a person’s innermost sense of themselves as male, female, a blend of both, or neither [1]. The American Psychological Association describes it as a deeply felt, inherent sense of being a boy, man, or male; a girl, woman, or female; or an alternative gender. This inner sense may or may not match the sex assigned at birth, and because it is internal, it is not necessarily visible to others [2].
The term gender identity was coined in the mid-1960s to describe this persistent inner sense of belonging to a gender category [3]. When a person’s gender identity matches their sex assigned at birth, they are described as cisgender. When it does not match, a person may describe themselves as transgender, an umbrella term that covers many different experiences and identities [1, 2, 3].
One more term matters here: gender expression. This is the outward presentation of gender through clothing, hairstyle, voice, and behavior. It is a separate concept again. A person’s expression may or may not match what society expects of their gender, and it may not match their inner identity either [1, 2].
Sexual orientation and gender identity side by side
| Question | Sexual orientation | Gender identity |
|---|---|---|
| What does it describe? | Who a person is attracted to | Who a person understands themselves to be |
| Core element | Emotional, romantic, and sexual attraction | Inner sense of being male, female, both, or neither |
| Common labels | Straight, gay, lesbian, bisexual, pansexual, asexual | Cisgender, transgender, non-binary, genderqueer |
| Points where? | Outward, toward other people | Inward, toward the self |
| Does one predict the other? | No | No |
Why scientists treat them as separate
The American Psychological Association states plainly that gender identity and sexual orientation are different constructs. Transgender people, like cisgender people, may be attracted to men, women, both sexes, or neither sex. Most people experience their gender identity, who they feel themselves to be, and their sexual orientation, whom they are attracted to, as separate phenomena [2].
A simple example shows why this matters. A transgender woman, meaning a person assigned male at birth who lives as a woman, can be attracted to men, women, both, or neither. If she is attracted only to men, she may describe herself as straight. Being transgender says nothing automatic about her orientation [1, 2].
What research says about where they come from
Science has studied sexual orientation far longer than gender identity, but neither is fully explained yet. Both appear to arise from a mix of biological and environmental factors, and researchers are careful not to overclaim.
For sexual orientation, twin and family studies have long shown a partly genetic basis. The largest study to date, published in Science in 2019, analyzed genetic and survey data from 477,522 people in the United States and United Kingdom [4]. It found five specific genetic locations linked to same-sex sexual behavior, but each had a tiny effect. Taken together, all measured genetic variants explained only about 8 to 25 percent of variation in the population. The authors concluded there is no single “gay gene,” that many genes each contribute a small amount, and that genetics cannot meaningfully predict any individual’s behavior [4].
A major review published in 2025 confirmed this picture. It describes same-sex sexual behavior as complex and polygenic, meaning influenced by many genes with small combined effects. The same review notes that such behavior has been documented in more than 1,500 animal species, and that evolutionary explanations for why related genetic variants persist remain under active study [5]. In short, biology plays a real but partial role, and the rest is still not understood [4, 5].
For gender identity, the science is younger and less settled. Older twin studies produced widely varying heritability estimates for gender-related traits, roughly 11 to 70 percent, but most used small samples and different definitions [6]. A large Swedish register study covering 2001 to 2016 examined siblings of people diagnosed with gender dysphoria. It found no pairs of same-sex twins where both had a diagnosis, while 37 percent of different-sex twin pairs both did, compared with only 0.16 percent of non-twin siblings. Because different-sex twins share a womb but not more genes than ordinary siblings, the authors suggested that shared conditions before birth, such as hormonal influences, may contribute to the development of gender dysphoria. They stressed that the causes of gender identity remain mostly unknown [6].
How medicine classifies these today
The history of medical classification explains a lot of current confusion. Homosexuality was listed as a mental disorder in the first edition of the American Psychiatric Association’s diagnostic manual in 1952, and the APA voted to remove it in 1973. The World Health Organization removed it from the International Classification of Diseases when the tenth edition took effect in 1992 [3].
For gender, the pattern repeated more recently. The American Psychiatric Association’s current manual, the DSM-5 and its 2022 text revision, uses the term gender dysphoria. This diagnosis centers on distress: a marked and persistent mismatch between experienced gender and assigned sex, lasting at least six months in adolescents and adults, that causes clinically significant distress or problems in daily life [6, 7].
In 2019, the World Health Organization went further. Its eleventh revision of the International Classification of Diseases, ICD-11, replaced “gender identity disorder” with “gender incongruence” and moved it out of the chapter on mental disorders into a new chapter on conditions related to sexual health. The WHO explains that this reflects current knowledge that trans-related and gender diverse identities are not conditions of mental ill-health, and that classifying them as such causes enormous stigma. The WHO also states that gender-variant behavior and preferences alone are not a basis for the diagnosis [8]. United Nations human rights experts welcomed the change as a major breakthrough that reduces stigma while preserving access to needed health care [9].
An international field study of 649 transgender adults in six countries, Brazil, France, India, Lebanon, Mexico, and South Africa, tested the new ICD-11 criteria and found them valid and even more specific than the DSM-5 approach, supporting the view that gender incongruence itself is not a mental disorder [7]. The diagnosis exists so that people who need gender-affirming care can access it, not because the identity is an illness [7, 8].
Myths and rumors, clearly separated from the facts
The following claims are myths. Each one is followed by what is actually documented in the research and by major health organizations.
Myth: “There is a gay gene.” Documented fact: there is no single gene for sexual orientation. A 2019 study of nearly half a million people found thousands of genetic variants with tiny individual effects, together explaining only 8 to 25 percent of population variation, and no reliable way to predict an individual [4]. A 2025 scientific review confirms this polygenic, complex picture [5].
Myth: “Transgender people are simply gay.” Documented fact: the two dimensions are independent. Transgender people may be straight, gay, lesbian, bisexual, or any other orientation [1, 2].
Myth: “Being lesbian, gay, bisexual, or transgender is a mental illness.” Documented fact: the American Psychiatric Association removed homosexuality from its diagnostic manual in 1973, the World Health Organization followed in 1992, and in 2019 the WHO moved gender incongruence out of its mental disorders chapter because it is not a mental health condition [3, 8, 9]. Distress, when it occurs, can deserve care. The identity itself is not a disorder.
Myth: “Therapy can change a person’s sexual orientation.” Documented fact: a task force of the American Psychological Association reviewed the research and concluded that such efforts are unlikely to be successful and involve some risk of harm. Studies documented negative effects including depression, anxiety, loss of sexual feeling, and suicidality [10]. United Nations experts have warned that attempts to forcibly “normalize” sexual attraction or bodies are linked to violence and abuse [9].
Myth: “You can tell someone’s orientation or identity just by looking.” Documented fact: gender identity is internal and not necessarily visible, and gender expression may or may not match social expectations [1, 2]. Attraction is even less visible.
Myth: “This is a new or purely Western phenomenon.” Documented fact: same-sex sexual behavior has been reported across human societies, with studies estimating 2 to 10 percent of people engaging in it either exclusively or alongside opposite-sex relationships [4]. Research on gender identity involves populations in Europe, Asia, the Middle East, Africa, and the Americas [6, 7], and the WHO classification is designed for global use [8].
A global snapshot of attitudes
Public opinion varies widely around the world, which helps explain why these topics are discussed so differently across regions. In the Ipsos LGBT+ Pride Survey 2025, covering 26 countries and about 19,000 adults, 72 percent agreed that lesbian, gay, and bisexual people should be protected from discrimination in employment, housing, and access to businesses, and 71 percent said the same for transgender people [11]. Support for same-sex marriage or legal recognition stood at 69 percent on average, though it has slipped in several countries since 2021 [11].
The survey also shows large differences between countries and generations, reminding us that no single national experience defines this topic. The terminology itself continues to evolve, and words and definitions change as understanding grows, something the American Psychological Association itself acknowledges in its guidance [2, 3].
Why the difference matters in real life
Knowing the difference between orientation and identity is not just academic. In health care, providers who understand the two can ask better questions and avoid wrong assumptions, and the WHO notes clear links between gender identity, sexual behavior, violence, and health needs [8]. In law, anti-discrimination protections often name sexual orientation and gender identity as separate grounds. In research and national statistics, surveys measure them as separate items so policies can be based on accurate data. And in daily life, it helps people ask respectful questions, about a partner rather than guessing, and about pronouns rather than assuming.
The bottom line
Sexual orientation is who you love. Gender identity is who you are. They develop through different, still partly mysterious pathways, they do not determine each other, and major medical and scientific bodies consider both normal variations of human experience. What harms health, the evidence consistently shows, is not the orientation or the identity itself, but the stigma and discrimination attached to them [2, 3, 8, 10].
Disclaimer: This article is for general education only and is not a substitute for professional medical, psychological, or legal advice. If you have feedback, spot a possible error, or want to suggest a correction, please contact us. We welcome reader input and will review all serious correction requests.
References
- [1] Sexual orientation and gender identity terminology and definitions, Human Rights Campaign
- [2] Key terms and concepts in understanding gender diversity and sexual orientation among students, American Psychological Association
- [3] Sexual orientation and gender identity: review of concepts, controversies and their relation to psychopathology classification systems, Frontiers in Psychology
- [4] Large-scale GWAS reveals insights into the genetic architecture of same-sex sexual behavior, Science
- [5] Emerging insights into the genetics and evolution of human same-sex sexual behavior, Trends in Genetics
- [6] Gender dysphoria in twins: a register-based population study, Scientific Reports
- [7] Validity of categories related to gender identity in ICD-11 and DSM-5 among transgender individuals who seek gender-affirming medical procedures, Archives of Sexual Behavior
- [8] Gender incongruence and transgender health in the ICD, World Health Organization
- [9] A major win for transgender rights: UN health agency drops ‘gender identity disorder’ as official diagnosis, UN News
- [10] Report of the APA Task Force on Appropriate Therapeutic Responses to Sexual Orientation, American Psychological Association
- [11] Ipsos Pride Survey 2025: majority are for anti-discrimination protections, but support slips for several LGBT+ issues, Ipsos
