Differentiating sex and gender in health research to achieve gender equity.

Effectively tracking progress on initiatives focused on gender equity requires clear differentiation between the terms sex and gender. Sex usually refers to a person's biological characteristics, whereas gender refers to socially constructed roles and norms. Although both terms are often treated as binaries, gender is a spectrum and sex may include intersex individuals. While the terms are interrelated, they are sometimes conflated or used interchangeably in health data. Their fundamental distinctions, however, have implications for the conduct of research and the design of interventions targeting sex- and gender-based health disparities. We use the example of coronavirus disease 2019 to show how conflating these terms in data collection makes it difficult to ascertain whether disparities in infection rates, morbidity and mortality are determined by sex or gender. Although the exact process of collecting data on sex and gender may need to be adapted for specific contexts, there are steps that can be taken so that health data better reflect the differences between these concepts. Possible actions include using a two-step data collection process to determine both sex and gender of individuals, and encouraging recognition of intersex, third gender, transgender and gender nonbinary people. There also needs to be acceptance and commitment by data collectors and research editors; for example, by using tools such as the Sex and Gender Equity in Research checklist. With clearer distinctions between these foundational terms and how they are used in health data, we can achieve more accurate research findings, better-tailored interventions and better progress towards gender equity.