Approaching the concepts of gender and sex in family planning research

Gender and sex are distinct constructs that shape family planning related experiences, outcomes, and opportunities. This commentary provides guidance to clinical and social science researchers on: 1) current definitions of gender and sex; 2) when and why capturing information about gender, sex, or both is relevant to family planning studies; 3) recommended language for each stage of the research process to accurately and affirmingly recruit participants, collect and analyze data, and disseminate findings; and 4) approaches for engaging with already collected data or published research. Failing to address gender and sex with clarity and intention in family planning research can lead to biased samples, biased instruments, and biased data, consequently limiting scholarly knowledge of family planning desires, abilities, experiences, outcomes, and preferences.