Sexual orientation is a term that describes an individual's emotional and sexual attraction to men, women, both sexes, or neither sex, and the sense of identity which stems from these attractions.
Sexual orientation is traditionally classified as heterosexual (attraction to the opposite sex), homosexual (attraction to the same sex), or bisexual (attraction to both sexes). Alfred Kinsey's research suggests, however, that rather than three distinct groups, people tend to sit somewhere on a spectrum ranging from exclusive attraction to the opposite sex to exclusive attraction to the same sex. The term asexual has recently been added to the spectrum, to describe people who are not attracted to either sex.