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Psychological aspects

As one form of behavior, the psychological aspects of sexual expression have been studied in the context of emotional involvement, gender identity, intersubjective intimacy, and Darwinian reproductive efficacy. Sexuality in humans generates profound emotional and psychological responses. Some theorists identify sexuality as the central source of human personality. Psychological studies of sexuality focus on psychological influences that affect sexual behavior and experiences. Early psychological analyses were carried out by Sigmund Freud, who believed in a psychoanalytic approach. He also proposed the concepts of psychosexual development and the Oedipus complex, among other theories.

Gender identity is a person's sense of their own gender, whether male, female, or non-binary. Gender identity can correlate with assigned sex at birth or can differ from it. All societies have a set of gender categories that can serve as the basis of the formation of a person's social identity in relation to other members of society.

Sexual behavior and intimate relationships are strongly influenced by a person's sexual orientation.

Sexual orientation is an enduring pattern of romantic or sexual attraction (or a combination of these) to persons of the opposite sex, same sex, or both sexes. Heterosexual people are romantically/sexually attracted to the members of the opposite sex, gay and lesbian people are romantically/sexually attracted to people of the same sex, and those who are bisexual are romantically/sexually attracted to both sexes.

The idea that homosexuality results from reversed gender roles is reinforced by the media's portrayal of gay men as feminine and lesbians as masculine. However, a person's conformity or non-conformity to gender stereotypes does not always predict sexual orientation. Society believes that if a man is masculine, he is heterosexual, and if a man is feminine, he is homosexual. There is no strong evidence that a homosexual or bisexual orientation must be associated with atypical gender roles. By the early 21st century, homosexuality was no longer considered to be a pathology. Theories have linked many factors, including genetic, anatomical, birth order, and hormones in the prenatal environment, to homosexuality.

Other than the need to procreate, there are many other reasons people have sex. According to one study conducted on college students (Meston & Buss, 2007), the four main reasons for sexual activities are physical attraction, as a means to an end, to increase emotional connection, and to alleviate insecurity.