A BIOLOGIC PERSPECTIVE ON SEXUAL ORIENTATION

Sexual orientation may be defined as the sustained erotic attraction t o members of one's own gender, the opposite gender, or both-homosexual , heterosexual, or bisexual, respectively. Interest in sexual orientat ion is as old as the science of psychology, yet many fundamental issue s remain unresolved. This article reviews research in the development and psychopathology of sexual orientation as well as the results of fa mily and twin studies. Research in genetic linkage, sex hormones, and brain differences also is discussed.