Heterosexuality is a sexual orientation in which an individual experiences sexual or romantic attraction primarily toward people of a different sex or gender. Colloquially it is often called being "straight." The term describes patterns of desire and partnership rather than a single behaviour, and it can coexist with a wide range of identities, roles, and cultural expressions.

Definition and common usage

In most contemporary discussions, heterosexuality refers to opposite‑sex attraction: for example, a man attracted to women or a woman attracted to men. The concept may be expressed in both biological and social terms depending on context. For definitions and general overviews, see definition, and for discussions of gender and attraction, see gender.

Heterosexuality exists on a spectrum of sexual orientations. Other commonly described orientations include homosexuality (same‑sex attraction), bisexuality (attraction to more than one gender), and asexuality (little or no sexual attraction). Social frameworks such as heteronormativity shape expectations about relationships and can influence how different orientations are perceived and treated, often producing unequal outcomes that fall under the broader category of discrimination.

Biological and developmental perspectives

Researchers approach sexual orientation from multiple angles. Many scientists propose that a combination of genetic, hormonal and developmental factors influence attraction. Prenatal hormonal environments and brain differences have been suggested as contributing factors; some studies examine structures in and near the hypothalamus when considering sexual behavior and attraction (hypothalamus). Comparative work that looks across many mammals aims to place human variation in a broader biological context, though no single biological cause fully explains human sexual diversity.

History, culture and social roles

How societies define and regulate heterosexual relationships has varied across time and cultures. In many historical and contemporary traditions, marriage and family systems were organized around opposite‑sex pairings. Major world religions articulate particular teachings on marriage and sexuality: for example, doctrines in the Catholic Church, some Christian churches, Islam, and Judaism often privilege heterosexual unions. Interpretations and practices differ widely within and between these faiths, and public policy on marriage and family rights has evolved significantly in many countries.

Social importance, rights and contemporary debates

Heterosexual relationships form one significant pattern of intimate life, but modern societies increasingly recognize a plurality of orientations. Debates over legal recognition of relationships, anti‑discrimination protections, and social norms continue in many places. Discussions about privilege and expectation—sometimes described as heteronormativity—highlight how social systems can advantage heterosexual people and influence cultural assumptions about families and sexuality.

Notable facts and cautions

  • Heterosexuality is one of several sexual orientations and should be understood alongside other patterns of attraction rather than as a universal norm.
  • Causes of sexual orientation are complex and not reducible to a single biological or social factor.
  • Religious and legal views on heterosexual marriage vary; see items on specific traditions for detailed perspectives: religious views.

Further reading and resources

The overview above is intended to describe common understandings of heterosexuality while noting scientific uncertainty and cultural variation. For in‑depth research or guidance on personal matters, consult reputable sources in medicine, social science and local law.