Sexual orientation describes the enduring pattern of emotional, romantic, and sexual attraction you feel toward other people. It’s one of the most fundamental aspects of human identity, shaped by a combination of biological factors and personal experience. As of 2024, 9.3% of U.S. adults identify as something other than heterosexual, a number that has risen steadily as social acceptance grows and language for describing orientation expands.
Understanding sexual orientation means looking at three distinct but related dimensions: who you’re attracted to, how you behave, and how you identify. These don’t always line up neatly, and that’s normal.
The Three Dimensions of Sexual Orientation
The American Psychological Association defines sexual orientation as a person’s sexual and emotional attraction to another person, along with the behavior and social affiliation that may result from that attraction. That definition contains three layers worth pulling apart.
Attraction is the internal experience: who catches your eye, who you fantasize about, who you develop feelings for. Behavior is what you actually do, which may or may not match your attractions. Identity is the label you choose for yourself based on how you understand your own experience. A person might feel attraction to more than one gender but only pursue relationships with one. Someone might engage in same-sex behavior without identifying as gay or bisexual, sometimes because of stigma, sometimes because they simply don’t feel the label fits. Adolescents in particular often experience same-sex attraction or behavior well before settling on any identity label, and the process of claiming that identity can be slow and nonlinear.
Types of Sexual Orientation
Heterosexual (straight) describes attraction to people of a different gender. It remains the most common orientation by a wide margin.
Homosexual (gay or lesbian) describes attraction to people of the same gender. Gay is used broadly and also specifically for men; lesbian refers to women attracted to women.
Bisexual describes attraction to more than one gender. Despite the prefix “bi,” many bisexual people understand gender as a spectrum rather than a binary. Bisexuality often functions as an umbrella term that covers several non-monosexual orientations.
Pansexual also describes attraction to more than one gender, though it’s typically defined as attraction “regardless of gender,” placing less emphasis on gender as a factor in who someone finds appealing. In practice, research shows that many bisexual and pansexual people conceptualize gender in remarkably similar ways, and the line between these identities is often blurry. Which label someone chooses tends to reflect personal resonance more than a hard distinction.
Asexual (ace) describes people who experience little to no sexual attraction. This is not the same as choosing abstinence. Some asexual people have no sexual desire at all, while others do. Some are sexually active; others are not. Many asexual people use what’s called the split-attraction model, which treats sexual attraction and romantic attraction as separate experiences. An asexual person might identify as “aromantic asexual” (no romantic or sexual attraction) or “biromantic asexual” (romantic attraction to multiple genders but little or no sexual attraction), for example.
Queer is a broad term some people use when other labels feel too narrow or when they want to signal that they fall outside heterosexual norms without specifying further. Once a slur, it has been widely reclaimed, though not everyone is comfortable with it.
What Shapes Sexual Orientation
Sexual orientation isn’t a choice. Decades of research point to a web of biological factors that influence it before you’re ever aware of it.
Twin studies estimate that genetics account for roughly 32% of sexual orientation. Researchers have identified potential genetic associations on the X chromosome and several other chromosomal regions, along with specific gene variants involved in regulating brain chemicals like dopamine. No single “gay gene” exists. Instead, many small genetic influences appear to contribute.
Hormone exposure in the womb plays a significant role. Higher levels of androgens (a group of hormones that includes testosterone) during fetal development are associated with lesbian orientation in women, while lower androgen exposure is linked to homosexuality in men. One well-documented pattern, known as the fraternal birth order effect, shows that each older biological brother a man has slightly increases his likelihood of being gay. The leading explanation is that a mother’s immune system gradually develops a response to certain proteins produced by male fetuses, subtly influencing brain development in later pregnancies.
Brain structure differs as well. Gay men tend to have greater thickness in certain brain regions compared to straight men, and the connectivity patterns between deep brain structures differ. Early research in the 1990s found that a small cluster of cells in the hypothalamus, a region involved in basic drives and hormonal regulation, was smaller in gay men and closer in size to what’s typically found in heterosexual women.
None of these factors is deterministic on its own. Sexual orientation emerges from a complex interaction of genetics, prenatal environment, and neurological development.
How Stable Is Sexual Orientation Over Time?
For most people, sexual orientation is stable across adulthood. A large longitudinal study tracking adults over a 10-year period found that about 2% reported a different sexual orientation identity at the end of the study compared to the beginning. Heterosexual identity was the most stable overall, with less than 1% of heterosexual men and about 1.4% of heterosexual women shifting to a different label.
Fluidity was far more common among people with minority sexual identities, and the patterns differed sharply by gender. Among women, both bisexual and homosexual identities were equally likely to shift, with roughly 64% of women in each group reporting a change over the decade. Among men, gay identity was relatively stable (about 10% changed), but bisexual identity stood out as particularly fluid, with 47% of bisexual men reporting a different identity by the study’s end.
These numbers reflect changes in how people label themselves, not necessarily changes in underlying attraction. Someone might shift from “bisexual” to “gay” as they gain clarity about their experience, or from “straight” to “bisexual” after recognizing attractions they previously dismissed. The capacity for this kind of fluidity appears to be greater in women than in men, and greater among people who already identify outside the heterosexual mainstream.
The Process of Figuring It Out
If you’re questioning your own orientation, that process has a recognizable shape. Psychologists have described it in stages, though real life rarely follows a tidy sequence.
It often starts with a vague sense of being different, sometimes long before you can name what the difference is. This can begin in childhood or adolescence and doesn’t necessarily involve explicit sexual feelings. Next comes confusion: you notice specific attractions or feelings that don’t match what you expected, and you’re not sure what they mean. Over time, you may begin to tentatively accept a new understanding of yourself and seek out others who share it. Eventually, for many people, this leads to a settled sense of identity that feels integrated into the rest of your life.
Not everyone moves through all of these stages, and the timeline varies enormously. Some people know with certainty in childhood. Others don’t arrive at clarity until their 30s, 40s, or later. Social environment matters: in communities where non-heterosexual identities carry heavy stigma, people are more likely to suppress or delay recognizing their orientation. The growing visibility of diverse orientations, including asexuality and bisexuality, has made it easier for people to find language that fits. As one research finding noted, many asexual people initially identified as bisexual or pansexual before discovering that asexuality existed as a concept and realizing it described their experience more accurately.
There’s no test that tells you your sexual orientation. It’s something you come to understand by paying attention to your own patterns of attraction, both sexual and romantic, over time. If you’re in the middle of that process, you’re in good company.