Homosexual orientation

Homosexuality is romantic attraction, sexual attraction or sexual behavior between members of the same sex or gender. As a sexual orientation, homosexuality is "an enduring pattern of emotional, romantic, and/or sexual attractions" to people of the same sex. It "also refers to a person's sense of identity based on those attractions, related behaviors, and membership in a community of others who share those attractions."

Along with bisexuality and heterosexuality, homosexuality is one of the three main categories of sexual orientation within the heterosexual–homosexual continuum. Scientists do not know the exact cause of sexual orientation, but they believe that it is caused by a complex interplay of genetic, hormonal, and environmental influences, and do not view it as a choice. They favor biologically-based theories, which point to genetic factors, the early uterine environment, both, or the inclusion of genetic and social factors. There is no substantive evidence which suggests parenting or early childhood experiences play a role when it comes to sexual orientation. While some people believe that homosexual activity is unnatural, scientific research has shown that homosexuality is a normal and natural variation in human sexuality and is not in and of itself a source of negative psychological effects. There is insufficient evidence to support the use of psychological interventions to change sexual orientation.

The most common terms for homosexual people are lesbian for females and gay for males, though gay is also used to refer generally to both homosexual males and females. The number of people who identify as gay or lesbian and the proportion of people who have same-sex sexual experiences are difficult for researchers to estimate reliably for a variety of reasons, including many gay or lesbian people not openly identifying as such due to homophobia and heterosexist discrimination. Homosexual behavior has also been documented and is observed in many non-human animal species.

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