Sexual orientation refers to an enduring pattern of emotional, romantic, and sexual attraction to men, women, both, or neither. The most commonly discussed categories are heterosexual, homosexual, and bisexual, though many people experience attraction along a continuum rather than in discrete boxes.

Orientation is distinct from sexual behavior and from gender identity. A person may identify as gay yet remain celibate, or may engage in same-sex behavior without considering themselves homosexual. Twin studies, hormonal research, and brain imaging have all been used to explore biological contributions, yet no single factor has been shown to determine orientation in every case.

Cross-cultural evidence shows that same-sex attraction appears in every society that has been carefully studied, though the social meanings attached to it vary widely. Most researchers treat orientation as a relatively stable characteristic that emerges early and is not chosen in the ordinary sense of the word.

• Enduring pattern of attraction
• Distinct from behavior and identity
• Appears across cultures
• Likely involves multiple biological and developmental influences

Scientific consensus holds that orientation is not a matter of moral choice or simple social contagion.