The History of the Gender Gap in Medical Research

Jessica Lauer
Mar 5
7 min read

Updated: Aug 6

Women’s Health and Clinical Trials

Women make up just over half of the U.S. population, yet for much of medical history, their health needs (beyond reproductive concerns) have been marginalized in research. Historically, women’s health issues were not prioritized, leading to significant gaps in medical knowledge and a lack of healthcare practices tailored to women’s needs. This disparity in research focus has long-term consequences for both the quality of healthcare women receive and the medications and treatments they are prescribed.

In 1985, the Public Health Service Task Force on Women’s Health Issues recognized this gap in research, concluding that the lack of focus on women's health concerns had compromised the quality of health information available to women. The report highlighted that medical research for women, outside of reproductive issues, was insufficient. Since then, a series of changes in research policies and practices have worked to correct this oversight, leading to more inclusive research on women’s health. However, there is still a long road ahead in achieving true gender equity in medical research.

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The History of Gender Gaps in Medical Research

The history of women in medical research is fraught with exclusion. For many years, women were either not included in clinical trials or were significantly underrepresented. A critical turning point occurred in 1993 with the NIH Revitalization Act, which mandated that women be included in clinical trials, ensuring that research studies would reflect the experiences and health needs of women as well as men. This legislation was pivotal, as it acknowledged the importance of including women as both subjects and researchers in medical studies.

Before this policy shift, a number of factors led to women’s exclusion from medical research. For example, the U.S. Food and Drug Administration (FDA) in 1977 issued a guideline that largely excluded women of reproductive potential from early-phase clinical trials. This exclusion was based on concerns about potential risks to pregnancy following the use of Thalidomide and the birth defects it caused. As a result, for years, women were left out of the initial phases of drug testing. This resulted in a significant shortage of data on how drugs and treatments would affect women.

Progress and the Continuing Fight for Inclusivity

While changes began in the 1990s, the road to gender equity in medical research has been a slow process. Over the years, a series of reports and recommendations from agencies like the Institute of Medicine (IOM) and government entities like the FDA and National Institutes of Health (NIH) have made strides toward promoting the inclusion of women in clinical trials. Notable milestones include the establishment of the Office of Research on Women’s Health (ORWH) by the NIH in 1990, and the creation of the FDA’s Office of Women’s Health in 1994. These offices were fundamental in promoting the inclusion of women in clinical trials and advancing women’s healthcare.

However, as late as 2022, a study from Harvard Medical School found that women remained substantially underrepresented in clinical trials for leading diseases. This underrepresentation continues to limit our understanding of how diseases affect women and how medications impact women differently than men. Even today, women still face challenges in clinical trials, from recruitment barriers to insufficient consideration of sex-based differences in medical research.

The Importance of Understanding Sex Differences in Clinical Trials

One of the major obstacles to understanding women’s health is the lack of research that accounts for biological sex differences. For decades, medical studies have often excluded or underrepresented women, especially in the early stages of drug trials. This lack of inclusion has hindered the development of effective treatments for women, as medications have often been tested primarily on male subjects, leaving women’s health needs largely unaddressed.

In recent years, however, there has been a push to ensure that clinical trials include both men and women and analyze the data based on sex. The NIH’s policy, instituted in 2016, now requires researchers to collect data on sex differences in preclinical research and animal testing. The goal is to ensure that scientific data is analyzed for any sex-based differences that could influence medical treatment outcomes. Furthermore, the NIH’s Office of Research on Women’s Health has developed strategic goals aimed at increasing sex differences research in basic science and promoting personalized healthcare for women.

Barriers to Gender Equity in Research

Despite policy changes and efforts to promote inclusivity, gender bias and other barriers remain. Some researchers, for example, avoid using female mice in studies because of the perceived complications of fluctuating hormones and reproductive cycles. The additional cost of using both sexes in animal testing and concerns about hormonal variations have led many researchers to default to using only male animals in preclinical studies. This continues to create a significant gap in the understanding of how diseases and treatments affect women.

Women of color are even further underrepresented in clinical trials. This lack of diversity in research contributes to healthcare disparities, as treatments that work well for one group may not be as effective or may even cause adverse effects in others.

The Impact of Underrepresentation

The consequences of excluding women from clinical trials are far-reaching. Women experience adverse reactions to medications at twice the rate of men, and one study even found that women with metal hip replacements were 29% more likely to experience implant failure than men, possibly due to anatomical differences that were never considered in the initial trials.

Heart disease, the leading cause of death for both men and women in the United States, also highlights the gender gap in medical research. For years, it was thought that heart disease presented similarly in men and women. However, it was only in 1999, when the American Heart Association published a guide to preventive cardiology for women, that the medical field acknowledged that women often experience different symptoms of heart disease than men. This lack of recognition led to women being misdiagnosed or not receiving the necessary treatment in time.

Moving Toward Gender Equity in Health Research

Despite progress, there is still much work to be done in ensuring gender equity in medical research. The gap in women’s health research is not just a matter of representation; it is a matter of justice. Women deserve treatments and medical care that are based on evidence reflecting their unique biological makeup and health concerns. Researchers, clinicians, and policymakers must continue to push for inclusivity in studies and work to eliminate biases that have historically led to the marginalization of women’s health.

Final Thoughts:

As we continue to make strides, it is clear that achieving equity in medical research requires more than just policy changes, it requires a cultural shift in how we approach science and healthcare. By prioritizing the inclusion of women and analyzing data with this knowledge, we can create a more inclusive, comprehensive healthcare system that provides the best possible care for everyone, regardless of gender. Until that happens, women will continue to face healthcare disparities that could have been avoided through more inclusive research. As we continue to advocate for greater inclusion of women in medical research, it's crucial for individuals to stay informed and engaged in discussions around women's health. By supporting research initiatives that prioritize gender diversity and representation, we can work towards ensuring that all women have access to the quality healthcare they deserve. Stay tuned for more updates and insights on the latest research in women's health, and join us in the journey to promote empowerment and well-being for all.

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Until next time,

The Health She Deserves

The Timeline of Women's Health and Medical Research

1962: After thalidomide, a medication used to treat morning sickness in Europe and Australia, results in more than 10,000 deaths and birth defects in babies, the United States strengthens the authority of the FDA.
1975: National Commission for the Protection of Human Subjects and Biomedical and Behavioral Research establishes new rule which includes pregnant women as a vulnerable research subjects
1977: The FDA guideline “General considerations for the clinical evaluation of drugs” excludes women of reproductive potential from participating in early phase clinical research, except for life-threatening conditions. This is broadly applied and essentially excludes most women of childbearing age from medical research.
1985: A report from U.S. Public Health Service Task Force on Women’s Health concludes “research should emphasize disease unique to women or more prevalent in women”.
1986: An NIH advisory committee recommends that women be included in medical research studies.
1988: FDA “Guideline for the format and content of the clinical and statistical sections of new drug applications” specifies the importance of examining data within NDA databases for differences in safety or efficacy in subgroup populations, including gender
1990: The NIH establishes the Office of Research on Women’s Health, which leads a variety of programs aimed at advancing research into women’s health and increasing representation of women as both participants and investigators in clinical research.
1991: Bernadine Healy, MD, is appointed the first female director of the NIH.
1993: The FDA reverses its 1977 guidance, officially mandating the inclusion of women in research unless there is a justification for exclusion (for example, if the disease only affects men).
1993: The U.S. Congress passes a law requiring inclusion of women in NIH-sponsored clinical trials.
1994: The FDA establishes the Office of Women’s Health, which is charged with promoting the inclusion of women in clinical trials and the advancement of women’s health care.
1994: The Institute of Medicine releases a report, “Women and health research” that calls attention to two forms of historical gender bias in the design and implementation of clinical trials.
1998: The FDA regulation “Presentation of safety and effectiveness data for certain subgroups of the population in investigational new drug application repots and new drug applications” states that NDAs must present safety and efficacy data by sex; FDA has the authority to refuse to file any NDA that does not analyze the safety and efficacy data appropriately by sex. Demographics of participants in its clinical trials must also be included in IND annual reports.
2000: The FDA regulation “Investigational new drug applications: amendment to clinical hold regulations for products intended for life-threatening disease and conditions” gives FDA authority to place a trial for a life-threatening disease or condition on clinical hold if sponsors exclude men or women only because of reproductive potential.
2001: The Institute of Medicine releases a report that demonstrates how sex difference influences biology and should be studied as a variable in clinical research.
2010: The Institute of Medicine releases a report “Exploring the biological contributions to women’s health: does sex matter?” that further establishes the importance of sex-based biology.
2022: A Harvard Medical School study finds that women, as of 2019, were still substantially underrepresented in clinical trials for leading diseases.