- Understand the biology of sexual behavior and motivation
- Understand the research that lead to our current understanding of sexual behavior
- Describe variations in sexual orientation and gender identity
What is Sexuality?
sexuality
Sexuality refers to people’s sexual interest in and attraction to others; it is the capacity to have erotic or sexual feelings and experiences. A person’s sexual orientation refers to their emotional and sexual attraction to a particular sex or gender.
Sexuality differs from sex assigned at birth, in that “sexuality” refers to the capacity for sexual feelings and attraction, while “sex assigned at birth” refers to how one’s anatomy, physiology, hormones, and genetics are classified (typically as male, female, or intersex).
Sexuality is also separate from gender identity, which is a person’s sense of their own gender, or sociocultural classification (i.e., man, woman, or another gender) based on, or in opposition to, their sex assigned at birth (i.e., male or female).
Sexuality may be experienced and expressed in a variety of ways, including thoughts, fantasies, desires, beliefs, attitudes, values, behaviors, practices, roles, and relationships. These experiences and expressions manifest themselves not only in biological, physical, and emotional ways, but also in sociocultural ways, which have to do with the effects of human society and culture on one’s sexuality. Some researchers believe that sexual behavior is determined by genetics; however, others assert that it is in large part molded by the environment. Human sexuality impacts, and is impacted by, cultural, political, legal, and philosophical aspects of life, and can interact with issues of morality, ethics, theology, spirituality, and religion.
Sexual Behavior
Like food, sex is an important part of our lives. From an evolutionary perspective, the reason is obvious—the perpetuation of the species. Sexual behavior in humans, however, involves much more than reproduction. This section provides an overview of research that has been conducted on human sexual behavior and motivation. The section will close with a discussion of issues related to gender and sexual orientation.

Physiological Mechanisms of Sexual Behavior and Motivation
Much of what we know about the physiological mechanisms that underlie sexual behavior and motivation comes from animal research. As you’ve learned, the hypothalamus plays an important role in motivated behaviors, and sex is no exception. In fact, lesions to an area of the hypothalamus called the medial preoptic area completely disrupt a male rat’s ability to engage in sexual behavior. Surprisingly, medial preoptic lesions do not change how hard a male rat is willing to work to gain access to a sexually receptive female (Figure 1). This suggests that the ability to engage in sexual behavior and the motivation to do so may be mediated by different neural systems.

Animal research suggests that limbic system structures such as the amygdala and nucleus accumbens are especially important for sexual motivation. Damage to these areas results in a decreased motivation to engage in sexual behavior while leaving the ability to do so intact (Figure 2) (Everett, 1990). Similar dissociations of sexual motivation and sexual ability have also been observed in the female rat (Becker, Rudick, & Jenkins, 2001; Jenkins & Becker, 2001).
Although human sexual behavior is much more complex than that seen in rats, some parallels between animals and humans can be drawn from this research. The worldwide popularity of drugs used to treat erectile dysfunction (Conrad, 2005) speaks to the fact that sexual motivation and the ability to engage in sexual behavior can also be dissociated in humans. Moreover, disorders that involve abnormal hypothalamic function are often associated with hypogonadism (reduced function of the gonads) and reduced sexual function (e.g., Prader-Willi syndrome). Given the hypothalamus’s role in endocrine function, it is not surprising that hormones secreted by the endocrine system also play important roles in sexual motivation and behavior. For example, many animals show no sign of sexual motivation in the absence of the appropriate combination of sex hormones from their gonads. While this is not the case for humans, there is considerable evidence that sexual motivation in humans varies as a function of circulating testosterone levels (Bhasin, Enzlin, Coviello, & Basson, 2007; Carter, 1992; Sherwin, 1988).