William J. Hall
Sexual orientation is a multidimensional phenomenon involving a person’s sexual attraction, sexual behavior, and sexual orientation identity. Sexual orientation patterns may remain consistent or fluctuate over time. Although heterosexual attractions, behaviors, and identities appear to be the dominant manifestations of sexual orientation, other sexual expressions exist. The causes of sexual orientation are still not completely understood; however, evidence suggests that biological factors play a strong role. Sexual development is an important part of human development, and there are parallel and differing developmental tasks and trajectories for those who are heterosexual and those who are queer. Non-heterosexual sexualities are often stigmatized, which contributes to homophobia and heterosexism. There is a continuing history in the mental health professions of efforts to change the sexual orientation of people who are queer, despite evidence of harm and ethical mandates. Researchers and service providers should assess sexual orientation because it is one of many important characteristics in the lives of individuals.