NIH uses sex/gender to indicate that either sex or gender may be reported for inclusion enrollment purposes. “Sex” refers to biological differences between females and males, including chromosomes, sex organs, and endogenous hormonal profiles, and is typically assigned at birth. “Gender” refers to socially constructed and enacted roles and behaviors which occur in a historical and cultural context and vary across societies and over time. More information about the distinction between sex and gender can be found at https://orwh.od.nih.gov/sex-gender.
When collecting and reporting information about sex/gender, it’s important to consider what is most relevant to the scientific question under study (e.g., sex at birth, current gender identity, etc.). The NIH encourages investigators to design their data collection instruments in a way that allows the participants to self-identify their sex or gender in a way that is meaningful within the study’s context. Participants always have the option not to identify with either sex/gender category. If both sex and gender identity are collected, investigators may choose which one to report based on the scientific question(s) that are the focus of the study.
For more details, see our FAQs.