Stereotypes of Sexual Behavior

Discoveries resulting from the study of sex and sex determination in mammals illustrate the inadequacy of stereotypical divisions of male or female. As the organizational concept makes clear, sexuality depends on subtle hormonal and genetic controls, not just on either-or labeling of male or female. This finding applies to all the tissues associated with reproduction, including the circuits in the brain that underlie sexual behavior. In most vertebrate species, adults usually exhibit mating behaviors characteristic of their own gonadal sex, known as homotypical sexual behaviors. Not infrequently, however, individuals also perform behavior patterns normally associated with the opposite sex, known as heterotypical behaviors. For example, females sometimes engage in mounting, and males sometimes solicit being mounted. Such heterotypical sexual behaviors are a frequent and important part of the social biology of many species, especially among mammals. Female cows commonly mount other females, a practice that seems to help synchronize the reproductive cycles of the herd. In rhesus monkeys, mounting functions as an indicator of dominance and so maintains an orderly social hierarchy. Even though embryonic hormones direct neuronal development, it seems that the brain never completely loses the dual circuitry that permits both homotypical and heterotypical sexual behavior. In reality, there is a considerable range of normal behavior exhibited by members of the human population. The tendency to categorize all sexual behavior into only two acceptable types associated with the phenotypic sex of the individual overlooks this range and the multiple genetic and environmental influences that contribute to behavior.

Adapted and excerpted from: Crews, David. 1994. Animal Sexuality. Scientific American 270(1):108-114. Click above for a sample sample quiz question.