Young woman during virus lab tests

The Reality of Gender Bias in Medical Research

Gender bias in medical research

What is gender bias in healthcare?  

Gender bias in medical research refers to the tendency at all levels of research to focus on one gender. This leads to knowledge creation with parameters defined exclusively by a single gender.   

Historically, cisgender males have been over-represented in all aspects of medical research. As a result, findings from men are applied to cisgender females and other gender identities who were not included in the studies. With differences in biology and social determinants of health affecting men and women, gender bias in healthcare can lead to poor health outcomes.   

In many cases, ‘women’s health’ refers only to the reproductive system and ignores all non-reproductive pathophysiology. In addition, females are underrepresented as authors in medical research, medical images, and laboratory animal studies.  

Recommended podcast CE course: What Lies Beneath: Implicit Bias in Healthcare 

Data gaps by gender  

Although gender disparities in medical research have been identified for generations, equity has yet to be achieved. Implications including drug safety, misdiagnosis, and decreased health outcomes for people who are not cisgender male remain relevant today.  

It wasn’t until 1994 that United States federal law required the National Institutes of Health to include women and diverse populations in federally funded research and to analyze the results by sex or gender. Despite basic biological differences between the cells of men and women, female lab animals are often not included in animal studies of drugs. If they are, the results are not reported by sex.   

After the thalidomide scandal of the 1950s, females of childbearing age have been considered too risky to include in studies. Without the ability to include women from puberty to menopause in studies, female-specific knowledge development has stalled. Prescribers often find this particularly frustrating when trying to treat pregnant women, as very little drug safety information is available.   

Steps toward equity  

While slow, there is evidence of improvement. One study of 38 drug trials found that, while Phase I drug trials participants were 22% female, Phase II and III trials were more evenly split between men and women (Labots et al., 2018).   

Concerns remain, however. Phase I trials determine basic side effects and safety profile information, and women remain underrepresented in that phase. This leads to knowledge gaps and safety concerns.   

Potential misdiagnoses  

The over-representation of biologically male participants in studies has impacted the diagnosis of disease as well. Most medical illustrations appear to show males. Typical disease presentations are often taken from studies that only included men or did not analyze responses by gender. This has led to a lack of understanding of how women manifest disease.   

The enduring example of this issue is the symptoms of myocardial infarction. Women may not present with the classic “elephant on my chest” crushing chest pain. Instead, women may report fatigue, nausea, arm pain, or neck pain. These dramatic differences in symptoms have led to misdiagnosis in women, which can be fatal.   

Clinicians may mistakenly attribute other symptoms in women, such as abdominal pain, to menstruation, missing a major abdominal pathology. Understanding the presentation of reproductive and non-reproductive diseases across sex and gender is crucial for population health.   

Expanding the discussion of gender  

These inequalities also harm men. Social norms may discourage men from participating in medical research or programs on topics such as weight loss or mental health. For this reason, studies examining prevention are more likely to include women, leaving out a critical demographic. 

As the definitions of sex and gender have expanded over time, there are new calls to expand the discussions of gender in health. Improving representation of expanded gender identities as both authors and participants is needed to improve equity in medical research.  

Professional disparities  

Despite advances in equity and equal representation in many fields of medicine, prestigious journals are less likely to publish female authors. They also receive fewer citations by other authors, decreasing the chances of receiving research funding. These findings suggest that a push for equity must be multifaceted and include all aspects of medical research.   

Gender disparities in medical research persist despite almost 30 years of federal law to promote equity in the largest funding body. Disparities continue at all levels, from basic bench science to the publication of completed studies in influential journals.   

The implications of these inequities include a lack of knowledge in certain areas, leading to misdiagnosis and treatment, which can prove fatal. As the understanding of sex and gender continues to expand, additional efforts will be needed to ensure equity and representation for all identities across medical research.   

By considering the shared and unique needs across genders, and providing gender-sensitive care, healthcare professionals can advance medical knowledge and provide equitable healthcare for all.   


  • Labots, G. Jones, A., de Visser, S.J., Rissmann, R., & Burggraaf, J. (2018). Gender differences in clinical registration trials: Is there a real problem? British Journal of Clinical Pharmacology, 84:700-7. doi:10.1111/bcp.13497.   
  • Murciano-Goroff, Y.R. (2015). Differences in the percentage of illustrations showing males versus females in general medicine and general surgery textbooks.  Medical Science Education, 25(2):123-126. doi:10.1007/s40670-015-0116-8 
  • Hawkes, S. Haseen, F., & Aounallah-Skhiri, H. (2019). Measurement and meaning: Reporting sex in health research. Lancet, 393(10171):497-499. doi:10.1016/S0140-6736(19)30283-1   
  • Mazure, C.M., & Jones, D.P. (2015). Twenty years and still counting: Including women as participants and studying sex and gender in biomedical research. BMC Womens Health. 1594. doi:10.1186/s12905-015-0251-9   
  • Muric, G., Lerman, K., & Ferrara, E. (2021). Gender disparity in the authorship of biomedical research publications during the covid-19 pandemic: Retrospective observational study. Journal of Medical Internet Research. 12;23(4):e25379. doi: 10.2196/25379.   
  • Merone, L., Tsey, K., Russell, D., & Nagle, C. (2022). Sex inequalities in medical research: A systematic scoping review of the literature. Women’s Health Reports. 3(1):49-59. doi: 10.1089/whr.2021.0083. Erratum in: Womens Health Rep (New Rochelle). 2022 Mar 16;3(1):344.   
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