Sofia Ahmed, MD, MMSc, FRCPC, FASN, FISN, President, Organization for the Study of Sex Differences
 

 

Jill Becker, PhD, Editor in Chief, Biology of Sex Differences

Kathryn G. Schubert, MPP, CAE, President and CEO, Society for Women's Health Research

Sex differences describe the spectrum in biological characteristics related to sex across individuals. This encompasses patterns typically associated with ‘male’ or ‘female’ as well as variation due to differences of sex development. In health care, this refers to differences in disease risk and prevalence, symptom presentation, and treatment choices and effectiveness. Research on sex differences, therefore, helps us to better understand the biological differences between males and females across the life cycle, allowing for evidence-based health decision-making that more effectively serves each population and brings us one step closer to personalized medicine. Ensuring that sex differences are considered across the research ecosystem is particularly important to close longstanding knowledge gaps affecting populations historically excluded from medical research, including women, pregnant and lactating populations, non-white populations, and minoritized sexual orientation and gender identity populations. Yet beyond addressing these gaps, applying sex differences research broadly is fundamental to advancing health care and achieving the United Nation's Sustainable Development Goal 3 (SDG3), ensuring healthy lives and promoting well-being for all at all ages.

This Sex Differences Awareness Day, May 12, affords us a moment to reflect on the significant impact sex differences research has had on health care, medicine, and scientific discovery – and to celebrate those who are spearheading this work. For this reason, the Society for Women’s Health Research (SWHR), the Organization for the Study of Sex Differences (OSSD), and the Biology of Sex Differences (BOSD) journal are joining together to amplify today’s message: Sex differences research is a key tenet of effective and meaningful health research; when we integrate sex differences into research, we learn more about everyone’s health.

Sex differences research, conducted intentionally and consistently, results in better health research. With sex differences research, we can:

• Advance personalized medicine and improve disease detection and prevention.
• Better grasp how health changes throughout the lifespan, including across hormone changes such as puberty and menopause, for both child and parent (3.2).
• Better understand how diseases change over the lifespan of males and females, particularly through hormone fluctuations and life stages like puberty, pregnancy, andropause and menopause.
• Improve the effectiveness of testing, treatment, and vaccinations (3.b) in an effort to end preventable deaths, particularly for women (3.1, 3.4).
• Ensure that health care services and treatments are equally safe and effective for all people (3.8), such as altering drug dosing recommendations based on sex.
• Identify sex-related differences in disease signs and symptoms. For example, heart attack symptoms common in male individuals (chest pain, pain in the left arm) may be distinctly different than the symptoms seen in female individuals (neck pain, back pain, heartburn, nausea, and excessive tiredness, in addition to chest pain).
• Understand the overlap of mental health and physical health (3.4).

 And this list merely scratches the surface of what we can learn through sex differences research.

Today is also an occasion to celebrate leaders in the field. Less than four decades ago, sex differences were not routinely accounted for in medical research in the United States, and in fact many female and non-white populations were systematically excluded from research. In 1990, SWHR was founded to address this gap and to advocate for the inclusion of women and minorities in clinical research. SWHR helped stand up Offices of Women’s Health across the United States federal government – within the U.S. Department of Health and Human Services (HHS), the National Institutes of Health (NIH), and the Food and Drug Administration (FDA) – and helped lead the passage of the NIH Revitalization Act of 1993, mandating that women and minorities be included in all NIH-funded clinical research and that Phase III clinical trials be analyzed for sex differences. In 2006, OSSD was established as part of SWHR to foster and promote scientific collaboration on sex and gender differences research and provide a home for facilitating interdisciplinary research. In 2010, OSSD became its own freestanding entity, and SWHR and OSSD co-founded the peer-reviewed, open-access academic journal Biology of Sex Differences, the official journal of OSSD. The journal aims to improve understanding of sex differences and foster development of therapeutic and diagnostic tools that are specific for sex differences research and better health outcomes. To date, the journal has published over 950 peer-reviewed articles, including 15 special collections, has an impact factor of 5.1 (2024), and had over 1.4M downloads in 2025.

This year, OSSD celebrates its 20^th anniversary, reflecting two decades of advancing the scientific understanding of sex and gender in health and disease. Over this time, the field has evolved from one in which sex and gender differences were often overlooked to one where their consideration is increasingly expected in rigorous, reproducible, and generalizable research. OSSD has played a central role in this transformation by fostering interdisciplinary collaboration and training the next generation of scientists. Looking ahead, we all have a remarkable opportunity to build on this momentum by embedding these advances across the health research continuum, from study design and analysis to translation into health care, with the goal of improving health outcomes for all.

This Sex Differences Awareness Day, we hope you will join us in celebrating the transformative effect of sex differences research on health care and medical innovation. Accounting for and analyzing sex differences leads to more comprehensive research and improves the effectiveness of treatment decisions. The result is clear: we all stand to gain healthier lives because of sex differences research.

Join us in recognition of Sex Differences Awareness Day!