In general, sex refers to biological, anatomical, physiological, and hormonal variations that, on average, distinguish females and males. By contrast, gender refers to the differences between men and women, boys and girls, that stem from how behaviors, abilities, responsibilities, and overall values are ascribed differentially to males and to females in a society. Sometimes separately, but more often through their interactions, sex and gender are important determinants of health.
For instance, there are sex-linked diseases (e.g., hemophilia) that only rarely and under exceptional circumstances affect women. There are also sex-specific cancers (e.g., of the prostate [men] and of the ovaries [women]), as well as specific conditions that, because of their biological exclusivity to males or females, can only occur in one or other sex (e.g., pregnancy-related conditions in women; testicular disorders in men). Generally, however, observed differences in the frequency of some health outcome between women and men do not reflect a sex (biologic) difference. Rather, most differences derive from a complex set of interactions between sex (biology) and gender (roles and expectations).
Every society has its own economic, social, cultural, and political arrangements that make being a woman different from being a man. The gender norms and expectations applied to women and to men that derive from these arrangements vary from place to place, change overtime, and are always affected by other features (e.g., age, class, ethnicity, sexual orientation, ability) that are attached to an individual. As a result of the gender differences assigned to them, individuals will experience their lives differently according to whether they are defined as male or female. Accordingly, women and men will have different exposures to different risks, different responses to the same exposures, different patterns to seeking treatment, and different needs for and responses to public
Consequently, to understand and respond to most human health and sickness issues, clarifying the interaction between sex-linked factors and gender-based factors is critical; the expectations, norms, and stereotypes associated with the roles of men and women play out in their health, strongly influencing symptoms, treatments, and policies.
As an example, consider the relation of work to health. Much research has shown that underemployment and lack of control over work situations or job demands are associated with increased levels of stress and poor health. These employment and working conditions differ according to gender, and women in the paid workforce in North America are more likely than men to have undervalued and underpaid jobs in the service sector, to work part-time, to have interruptions of their careers because of family responsibilities, and to experience high-demand, low-control conditions at work. All these factors influence their risks for (exposure to) disease, what they do when ill, how health care professionals respond to and treat them, and what public policies of work-related health promotion and health protection are developed.
Thus, to examine the relation of work to health without accounting for the influence of gender would be to ignore how women may be exposed to health-damaging agents unlike those their male colleagues face; how they may have less access to private health care (United States) or necessary medications that must be paid for out-of-pocket (United States and Canada); and how they may have reduced opportunities to attend health programs, such as screening programs, because after-work hours are filled with child-care duties more often for women than for men. Furthermore, to the extent that work in the home is still more likely to be defined as "women's work," her gender, and not her biology, means that a woman may be more exposed to harmful household cleaning agents and neighborhood environmental contaminants, to the stresses that come from trying to balance child and elder-parent care with paid employment, and to reduced (if any) time for recreational exercise and other health-promoting activities.
Until the early 1990s, most health research was conducted on men on the assumption that the information gained could be applied simply and straightforwardly to women. The major exceptions were diseases and conditions that occurred only (e.g., pregnancy) or primarily (e.g., breast cancer) in women. Yet, what is learned from studying males may not apply to the health of women.
Similarly, in developing public health policies and interventions, there has been an assumption of "gender neutrality," that is, not taking account of whether men or women were the subjects. It is now apparent that this approach is not only an oversimplification, but actually incorrect. The options that women and men have, and the decisions they are able to make, including their employment, smoking behavior, and sexual and other activities, will generally, if not always, be constrained by how male and female roles are defined in any society.
For example, consideration of the role of gender is essential to understand infection with HIV (human immunodeficiency virus). Males and females may have some biological differences in the probability of contracting the virus following exposure, but their risks of exposure are more than biological. For instance, if women in a society are dependent on men for economic security, their ability to demand safer sex practices will be limited; if they are seen as the primary child-care providers, their parenting roles, not those of their male partners, may be proscribed and/or constrained by law.
Neither sex nor gender can, on its own, provide complete understanding of most matters of health and disease. Sex differences (deriving from hormonal and/or anatomical variations) may affect the ways in which men and women experience the symptoms of a heart attack, but gender-related factors will influence whether or not medical treatment is sought by the individual and how a health professional responds to the person presenting these symptoms. Similarly, while sex differences (as in metabolism) may affect the efficacy of drug treatment for a heart problem, gender-related factors may influence whether or not the costs of the medication can be afforded, whether or not the medication can be taken on the schedule prescribed, and whether social interventions (e.g., stress reduction, exercise, and dietary changes)