Biological Factors in the Development of Sexual Orientation

Abstract

Abstract The purpose of this chapter is to review evidence on the role of biological factors in the development of sexual orientation from sources as diverse as studies of lateral preference, cognitive abilities, and anthropometry. Homosexuality is a sexual attraction to someone of the same anatomical sex; heterosexuality is a sexual attraction to someone of the opposite sex. Closely allied to sexual attraction is fantasy. If someone has sexual fantasies about others of the same sex, then the fantasies are homosexual; if someone has sexual fantasies about others of the opposite sex, then the fantasies are heterosexual. If a person’s sexual attractions and fantasies are primarily homosexual, then that person may be labeled “lesbian” or” gay.” Conversely, if a person’s sexual attractions and fantasies are primarily heterosexual, then that person may be labeled “heterosexual.” When attraction and fantasy are directed to members of both sexes, a person may be labeled “bisexual.” Attraction and fantasy are not the only dimensions that could be used to define a person as lesbian, gay, bisexual, or heterosexual, but they are typically the most reliable. Physiological responses to erotic stimuli are one alternative, but men and women respond differently to stimuli of different sensory modalities (Laan & Everaerd, 1995), thereby rendering difficult unambiguous comparisons between men and women. Same-sex sexual behavior or opposite-sex sexual behavior could serve as another criterion for sexual orientation, but personal and environmental constraints on sexual activity restrict its usefulness. Asking individuals whether they would self-identify lesbian, gay, or bisexual is another possibility, but this has the limitation that responses to this question are often based on social and political aspects of homosexuality and not sexual desire. Nonetheless, attraction/ fantasy, physiological responses, behavior, and self-identity are significantly, but not perfectly, positively correlated.