Abstract
The conflation of sex and gender in sport and exercise science research has led to gaps in representation and understanding of gender-inclusive outcomes. This invited editorial presents a framework to guide researchers in conducting statistical analyses that account for multiple gender identities beyond the traditional binary classification. The invited editorial guides deliberation on whether to test for sex or gender differences in sport or exercise science research. It prompts investigators to answer the question, "Is there a valid, literature-supported rationale for investigating sex or gender differences?" If "yes", we propose approaches that may help investigators plan a study for two sex or gender groups, or in situations with three or more sex or gender groups. The editorial provides a valid, step-by-step statistical decision framework to ensure a robust, and ethical, research design while addressing the limitations of current sex- and gender-based classifications in sport and exercise science. By adopting gender-inclusive research practices, the field can better support equitable exercise prescriptions, rehabilitation strategies, and training periodization for diverse populations.