The article discusses the importance of including female participants and animal subjects in biomedical research, particularly in the study of sex differences. Despite progress, challenges remain, including societal attitudes and the misuse of findings. The authors argue that comparing female and male individuals is essential for understanding biological sex differences, which have significant implications for health and disease. They highlight several areas where sex differences have been crucial, such as immune function, chronic pain, and mental health. The authors emphasize the need to balance biological and social determinants of disease and to address the misuse of sex differences to justify historical subordination. They conclude by advocating for continued research on sex differences, while also recognizing the importance of considering both biological and social factors.The article discusses the importance of including female participants and animal subjects in biomedical research, particularly in the study of sex differences. Despite progress, challenges remain, including societal attitudes and the misuse of findings. The authors argue that comparing female and male individuals is essential for understanding biological sex differences, which have significant implications for health and disease. They highlight several areas where sex differences have been crucial, such as immune function, chronic pain, and mental health. The authors emphasize the need to balance biological and social determinants of disease and to address the misuse of sex differences to justify historical subordination. They conclude by advocating for continued research on sex differences, while also recognizing the importance of considering both biological and social factors.