Biology is the dominant basis for understanding sexuality in our cul­ture. By biology I mean evolved, physiologically based dispositions that provide explanations for sexual phenomena such as level and object of sexual desire. Thus, a reductionistic approach is assumed in which capacity for sexual desire is biologically based. Tiefer (1987; chapter 4 this book) has eloquently argued that biology has a privileged position in sexual dis­course, based on the assumption that the body comes before everything else. “It is the original source of action, experience, knowledge, and mean­ing for the species and the individual” (p. 81). This explanation posits that both women and men are motivated by inborn biological drives. A basic tenet of Freudian psychology, for example, is that human behavior is mo­tivated by instinctual drives, and that chief among them is the biologically based sexual instinct. Although Ttefer’s argument primarily addresses sex researchers and why they have clung to a medicalized interpretation of sexuality, she also addresses motivation among the general public to un­derstand sexuality from a medical viewpoint. She argues that a biological understanding of sexual desire, focusing on involuntary actions of hor­mones and blood vessels, takes responsibility away from individuals who wish to absolve themselves of traditional charges of sinful behavior.

I would like to suggest additional reasons why people support the notion that sexual motivation is biological. Sexuality, and especially gender differences in sexuality, are seen as biologically rooted in the same way that all gender characteristics are popularly believed to be biologically rooted. People focus on the inevitability, rather than the social construction, of gender characteristics. Belief in the inevitability of these differences helps support them. Thus it is popular belief not only that the gender differences discussed above exist, but also that they are biologically rooted.

Thus it is believed that men have a stronger sex drive than women and that men’s strong sex drive compared with women’s weaker sex drive is biologically determined. A corollary of this supposition is that it is phys­ically harmful for men to not fulfill their sexual desires. This is especially the case once the arousal process has begun. The existence of a sex drive with these characteristics in men has various social consequences. One consequence is that men will naturally initiate sex more than women. Consequent to this is that women have some moral obligation to help men gratify their sexual desires. This view is based not only on the need to not harm men physically but also on the presumption that this strong sex drive in men is necessary for preservation of the species (the sociobiological theory) and a belief in a biological basis for male superiority, so that if men have an important physical desire, it should not be thwarted. A further social consequence is that men cannot be expected to decline irresponsible sexual behavior because their urges overwhelm them, and they will natu­rally have an inclination to have sex regardless of the nature of the rela­tionship with a partner.

A second corollary is that women’s bodies are intrinsically arousing to men in ways that men’s bodies are not intrinsically arousing to women. In combination with men’s presumed stronger sex drive based on a biolog­ical need for sex, this justifies the objectification of women’s bodies for male sexual pleasure, as is found in pornography and advertising.

It is a paradox within this model that although women are supposed to have weak sex drives, their uncontrolled sexual behavior is seen as threatening. A staple of pornographic literature is the lustful woman who will stop at nothing to satisfy her powerful sexual urges. Sociobiology fur­ther explains the need to tightly control women’s sexuality. According to this perspective, people are motivated to achieve reproductive success, maximizing the number of genes passed on to the next generation. If two parents are required to successfully raise children, men make a substantial investment through monogamy. It is therefore critical to make certain that the child being raised by a man is in fact his biological progeny. To assure this, his female partner must be monogamous, with any extramarital sexual activity strongly discouraged. Economic reasons further dictate that if an­other man can make a paternity claim to offspring, the economic value of the child may be compromised.

A relational conceptualization is an alternative to the biological ex­planation. This is compatible with the social role explanation for gender differences in human behavior (Eagly & Wood, 1999) in that the assump­tion is made that gender differences arise from the different social roles that men and women tend to occupy. However, the proposed conceptu­alization goes further in focusing on the relational nature of sexuality which is not explicit in the social roles explanation.

The relational approach emphasizes the importance of defining and locating sexuality primarily in personal and relational, rather than physical terms” (p. 81). If one adopts a relational conceptualization of sexual mo­tives, then it makes sense that behaviors and even self-perception will be guided by socially, as opposed to biologically, derived gender roles. The relational model goes further in positing that individuals make sexual de­cisions to enact relational goals (e. g., achieve greater closeness or intimacy or assert dominance).