Enduring emotional, romantic, or sexual attraction to individuals of one's own gender.

For most of history, open discussions about homosexuality—sexual attraction to people of one's own gender—have been taboo. Men and women with a homosexual orientation are referred to as gay, while the term lesbian refers to women only. Homosexuality was classified as a mental disorder until 1973, when the American Psychiatric Association removed "homosexuality" from the Diagnostic and Statistical Manual of Mental Disorders. Two decades later, bias and discrimination against gays and lesbians still exists, but sexual orientation is discussed more openly.

There are no reliable statistics on the number of people who are homosexual. The American researcher Alfred C. Kinsey conducted extensive surveys on sexual behavior in the 1950s, and estimated that about 4% of men and 3% of women were exclusively homosexual; however, his research found that 37% of men and 28% of women had had some sexual...