“Sex” and “gender” are analytically distinct but not independent terms. They should be clearly defined when reporting research results. Sex and gender also interact in important and complex ways (see Analyzing how Sex and Gender Interact). Rarely does an observed difference between men and women involve only sex and not gender, and rarely does gender operate outside of the context of sex. The precise nature of their interaction will vary depending on the research question and other factors, such as socioeconomic status, or geographic location, interacting with sex and gender (see Analyzing Factors Intersecting with Sex and Gender). Some investigators use the term "sex/gender" to refer to the inter-relatedness of sex and gender, i.e., to "phenomena that are simultaneously biological and social" (Fausto-Sterling, 2012; Springer et al., 2011). Nancy Krieger (2003) has developed other terms for this inter-relatedness: "biologic expressions of gender" and "gendered expressions of biology."
1. Biological sex influences socio-cultural gender.
- Example (Engineering): In some cultures, differences in rates of education between boys and girls are influenced by biological sex differences. For example, lack of good water infrastructure can discourage girls from attending school. Menstruation increases girls' need for clean latrines and privacy at school. In Uganda, for example, dropout rates for girls rise dramatically around age 12-13, consistent with menarche (see Case Study: Water Infrastructure).
2. Socio-cultural gendered behaviors influence sex differences in biology.
- Example (Health & Medicine): Gender roles interact with sex in determining osteoporosis risk. Sex differences in osteoporosis incidence, long attributed to biological sex, may result in part from gendered behaviors that influence diet, sun exposure, and weight-bearing exercise (see Case Study: Osteoporosis Research in Men).
