Dr. Jane Vermunt, a Research Fellow in Nephrology and Hypertension at Mayo Clinic in Rochester, MN, reviews her article appearing online ahead of proof and in the October 2020 issue of Mayo Clinic Proceedings, where she offers biological explanations behind the sex disparity for COVID-19 disease outcomes. She notes the more severe COVID-19 disease outcomes in males, the role of gendered behaviors and highlights sex specific biological differences regarding immunomodulation and the renin angiotensin aldosterone system. She emphasizes knowledge of these and other biological sex differences can aid in risk stratification, prevention and effective treatment. Available at: