Historically, medical research has been male-dominated in terms of subjects as well as researchers, even though women make up half of the world’s population. As a result of this gender bias, insights into various diseases and findings about medications have often been extrapolated from men and applied to women. But women aren’t just smaller men. Women’s bodies are decidedly different from men’s, with unique organs, genes, hormones, and other key differences.

It’s not surprising, then, that men and women experience many of the same diseases but develop different symptoms. With heart attacks, for example, the most common symptom is chest pain for men and women—but women may be more likely to experience other symptoms, such as shortness of breath, nausea or vomiting, or jaw pain. Women and men also metabolize and respond to many drugs differently. And there are gender-based variations in the physiological mechanisms underlying pain.

Some of these differences have been revealed through research that features gender parity. But many basic questions remain about how different health conditions and responses to drugs, vaccines, and other interventions are influenced by biological sex. “Within the last 10 years, there has been major progress on sex-informed research,” says Dr. Hadine Joffe, executive director of the Mary Horrigan Connors Center for Women’s Health and Gender Biology at Brigham and Women’s Hospital and a professor of psychiatry in the field of women’s health at Harvard Medical School. But “it’s a mixed story because there’s still such a long way to go.”

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