This chapter looks at the role of sex and gender in health-related research and their impact on women’s health. Ongoing challenges in health research include the underrepresentation of women as research participants, failure to account for sex and gender in research design and data analysis, biological essentialism, lack of respect for women’s agency regarding research participation and gender bias in the delivery of healthcare. Sex and gender must be systematically factored into all stages of research from conception to publication. A gender-based approach to preclinical and clinical research will improve the safety and efficacy of medical care for women and reduce the time to translate research into clinical practice.