Early on in the COVID-19 pandemic, physicians observed that men were more likely to die or to require treatment in an intensive care unit than women. This observation was later confirmed in a study of 10,600 adult patients in our health system, reminding us yet again that, for most diseases, biologic sex — which is to say, the sex you were assigned at birth — influences the susceptibility, symptoms, clinical course and response to treatment.

We are physicians and scientists, but we’re not so cloistered in our gleaming labs and exam rooms as to ignore the robust discussion unfolding about sex, gender and the way the two intersect and shape our understanding of ourselves and of others. We believe these discussions are fruitful and important tools to understanding and overcoming years of misrepresentation and discrimination.

And yet, as physicians, we want to interject an important reminder that often gets lost in the noise: While gender is a changing social construct we use to describe our perceptions about the respective roles of men and women, it is also true we all have a biologic sex. As COVID just reminded us, it is extremely important when treating patients not to lose sight of this biologic sex — as we run the risk of doing, say, when we speak of “birthing people” instead of birthing women — and how it might contribute to the progression of a disease.

Over the past several decades, women have been treated by clinicians and scientists as if they were just like men with a “one size fits all” approach to clinical care. But men and women are biologically different. We need more research to explore the genetic, anatomic, hormonal, immunologic and other factors that lead to the sex differences in all diseases, which will provide clues to how best to prevent and treat all affected individuals. This has correctly prompted the federal National Institutes of Health to require researchers to factor sex as a biological variable as a foundational part of the design, analysis and reporting of all studies it funds. This decision benefits not only women but men as well, paving the way to the much-needed practice of precision medicine in which biological sex is baked into the research, not just hammered into it as an afterthought.

The implications of this approach are likely to be considerable, and go a long way to helping us save lives, as some diseases affect one biologic sex much more commonly than the other. For example, rheumatoid arthritis, multiple sclerosis and migraines are diagnosed overwhelmingly in women, and certain liver diseases are more common in women than in men, such as autoimmune hepatitis and primary biliary cholangitis. In fact, the standards laboratories currently use when analyzing bloodwork are largely calibrated to reflect baselines corresponding to male biology, putting women at risk of misdiagnosis.

Studying biologic sex differences is not just a women’s health issue. Understanding the reasons for the differences between men and women help elucidate the mechanisms of disease, which helps everyone.