In 1948, Alfred Kinsey caught the world by surprise when he published "Sexual Behaviour in the Human Male", the first bestseller about sex. Kinsey had conducted extensive research into many aspects of human sexuality, and proposed a seven-point scale of sexual behaviour:
0 = exclusively heterosexual
1 = predominantly heterosexual, incidentally homosexual
2 = predominantly heterosexual, but more than incidentally homosexual
3 = equally heterosexual and homosexual
4 = predominantly homosexual, but more than incidentally heterosexual
5 = predominantly homosexual, incidentally heterosexual
6 = exclusively homosexual
Although Kinsey developed the scale to stress a continuum of sexuality, his study has generally been cited to prove that ten percent of the population is gay. This famous number, although politically useful for establishing the presence of a gay population, is probably inaccurate. Kinsey’s continuum was based on counting orgasms, and this measure of sexual identity misrepresents contemporary gay, lesbian, and bisexual identity.
Even though the Kinsey scale was conceptualized as a continuum, it is essentially a bipolar scale that presents homosexuality and heterosexuality as exclusive of each other. There is little clarity as to what is measured by the middle section. Kinsey surely intended to show degrees of bisexuality, but falling between the two extremes could mean that one is both homosexual and heterosexual or that one is neither. (Someone with little sex drive and few social desires for anyone might show up at "3" on the Kinsey scale, but so would someone with strong sexual desires for both men and women).