“Sexual Orientation” refers to the sex of those to whom one is sexually and romantically attracted.
Categories of sexual orientation typically have included attraction to members of one’s own sex (gay men or lesbians), attraction to members of the other sex (heterosexuals), and attraction to members of both sexes (bisexuals).
While these categories continue to be widely used, research has suggested that sexual orientation does not always appear in such definable categories and instead occurs on a continuum (e.g., Kinsey, Pomeroy, Martin, & Gebhard, 1953; Klein, 1993; Klein, Sepekoff, & Wolff, 1985; Shiveley & DeCecco, 1977).
In addition, some research indicates that sexual orientation is fluid for some people. This may be especially true for women (e.g., Diamond, 2007; Golden, 1987; Peplau & Garnets, 2000).