The article discusses the importance of considering sex and gender in the diagnosis, treatment, and prevention of diseases. It highlights how sex differences in genetics, epigenetics, and hormones influence physiological responses and disease outcomes, while gender constructs affect behavior, healthcare-seeking behaviors, and treatment responses. The review focuses on major chronic diseases such as heart disease, cancer, chronic pulmonary disease, stroke, Alzheimer's disease, diabetes, influenza and pneumonia, and chronic kidney disease. It emphasizes the need for sex-specific and gender-specific approaches in medical research and practice to improve outcomes for both men and women. The article also addresses the historical underrepresentation of women in clinical trials and the impact of these disparities on disease diagnosis and treatment.The article discusses the importance of considering sex and gender in the diagnosis, treatment, and prevention of diseases. It highlights how sex differences in genetics, epigenetics, and hormones influence physiological responses and disease outcomes, while gender constructs affect behavior, healthcare-seeking behaviors, and treatment responses. The review focuses on major chronic diseases such as heart disease, cancer, chronic pulmonary disease, stroke, Alzheimer's disease, diabetes, influenza and pneumonia, and chronic kidney disease. It emphasizes the need for sex-specific and gender-specific approaches in medical research and practice to improve outcomes for both men and women. The article also addresses the historical underrepresentation of women in clinical trials and the impact of these disparities on disease diagnosis and treatment.