Extreme fatigue, nausea, exhaustion, difficulty concentrating, perhaps heart palpitations or a vague pressure in the back or jaw: with these symptoms, a woman consults her doctor – but what is the underlying cause? The diagnosis is often unclear. In contrast, the “classic” presentation in men is well-known: severe pain in the left chest radiating into the arm, cold sweats, collapse. The diagnosis seems obvious: myocardial infarction – immediate hospitalization. What many people do not realize is that the woman, too, may be experiencing a heart attack. However, her symptoms do not match the “typical” textbook description that has been taught for decades – because that description is largely based on male patients (Fig. 1). The often more nonspecific symptoms reported by women are far less widely recognized [1]. As a result, women arrive at the emergency department about two hours later than men and receive treatment correspondingly later [2]. In critical situations, those two hours can mean the difference between life and death.
This example is representative of what is known as the Gender Health Gap. For centuries, medical research was oriented toward the male “default” body. Diseases primarily affecting men were studied more intensively, and symptoms reported by male patients were considered the medical standard. The consequences are still felt today: conditions that primarily or exclusively affect women were long neglected. At the same time, sex-specific differences in symptom presentation and disease progression continue to result in delayed or incorrect diagnoses for those who do not fit the male reference model [3]. On International Women’s Day 2026, we take a closer look at how women have been systematically underrepresented throughout medical history – and why medicine must now begin to close centuries-old research gaps.
1) Invisible Patients: Gender Bias in Research
2) Sex-Representative Studies – Who Is (Not) Being Researched?
3) Structures in Motion: On the Path Toward Sex- and Gender-Sensitive Medicine
The Gender Health Gap describes a structural inequality in the medical care of women and men. It arises particularly where data are not collected, analyzed, or interpreted separately by sex – most often to the detriment of women. When biological sex is not systematically considered in study design, implementation, and analysis, relevant differences in symptom presentation, disease progression, and treatment response remain invisible. A differentiated approach to sex and age is therefore not an optional add-on variable, but a fundamental prerequisite for valid research outcomes. This becomes especially evident in cardiovascular medicine: the previously mentioned example of myocardial infarction illustrates how strongly diagnostics and treatment have historically been aligned with a male reference model (Fig. 1). Yet the problem is by no means limited to cardiology. In many other medical fields, significantly less data are available for women – for example, in pharmacotherapy [1].
For some time now, it has been known that women experience adverse drug reactions more frequently or more severely than men. One key reason is that many medications were predominantly developed and tested in male study participants, while sex-specific differences in metabolism were insufficiently considered [1]. Factors such as hormonal status, enzyme activity, body composition, fat distribution, gastrointestinal transit, and kidney function significantly influence pharmacokinetics – that is, the absorption, distribution, metabolism, and excretion of a drug within the body.
These processes can differ considerably between women and men. Nevertheless, findings derived primarily from male participants up until the 1990s were directly translated into general medical practice. Standard dosages were often based on the male reference body, with the result that women frequently received the same dose – even though their bodies process drugs differently. In the worst cases, this led to severe adverse effects or life-threatening complications [2].
For decades, male study participants, perspectives, and decision-making structures have shaped not only society, but also medical research. Gender-equitable science therefore begins with a fundamental question: Who is actually being studied – and who is not? Women remain underrepresented in many clinical trials, particularly in the early phases of drug development and in sports and exercise science [5, 6]. Cyclical hormonal fluctuations, potential pregnancies, or the perceived “complexity” of female physiology are frequently cited as methodological challenges – and not infrequently serve as reasons for exclusion. Yet even when women are included, systematic sex-specific analysis is often lacking. Data are not evaluated separately, and differences related to menstrual cycle phase, age, or hormonal status remain unaddressed [7]. Gender bias often begins as early as the preclinical stage: to this day, basic research experiments are still predominantly conducted on male laboratory animals to reduce variability, costs, and experimental complexity [8].
Regulatory change came only gradually. In the United States, a guideline requiring that new drugs also be tested in women has been in place since 1994. In the European Union, the mandatory inclusion of women in clinical trials was not formally established until 2005 [2]. However, a simple 50:50 distribution is not sufficient to generate gender-equitable evidence. What truly matters is that study populations reflect the actual distribution of disease – that is, they should be aligned with how frequently a condition occurs in women and men. Equally essential is mandatory sex-specific data analysis. Undoubtedly, this increases the complexity, methodological effort, and costs of clinical research. In the long term, however, it improves data quality – and thereby enhances diagnostics, treatment, and safety for all genders.
Awareness of the gender data gap is growing – and with it, the willingness to rethink medical research and healthcare delivery. Political and institutional initiatives are increasingly setting impulses to close existing data and knowledge gaps. In July 2024, the German Federal Ministry of Education and Research (BMBF) published a funding directive titled “Interactive Technologies for Gender-Specific Health.” By 2028, approximately €15 million will be invested in projects that systematically investigate sex-specific aspects of medicine and develop innovative solutions [9]. Change is also emerging in medical education: gender medicine is set to become a mandatory component of medical training. To date, however, the integration of sex- and gender-sensitive content into the curricula of German universities remains inconsistent and highly dependent on the institution [10]. The education of future physicians is crucial, as it shapes how routinely sex-specific differences are considered in diagnostics and treatment.
A central component of modern gender medicine is the recognition of intersectionality. Women – like people of other genders – are not a homogeneous group. Health risks, healthcare experiences, and treatment outcomes vary depending on age, sexual orientation, migration background, disability, socioeconomic status, and other social determinants [3]. Sex- and gender-sensitive medicine therefore goes beyond the consideration of biological differences alone. It integrates both biological and sociocultural factors in order to provide care that is as equitable and personalized as possible [1]. To realistically reflect the diversity of the population, research must adopt an intersectional perspective – and move beyond a purely binary understanding of gender.
Today, it is clear that sex influences symptoms, disease progression, drug responses, and treatment outcomes. Sex- and gender-sensitive medicine is therefore essential for equitable and effective healthcare. Sustainable change requires systematic measures – from careful study design and sex-specific data analysis to the integration of these principles into medical education.
By the way: gender medicine does not only concern women – men benefit from it as well! Depression, for example, is still often perceived as a “typical female disease,” which means it is frequently underestimated or misdiagnosed in men. At the same time, many people are unaware that men can also develop osteoporosis or breast cancer [10].
[1] https://www.apotheken-umschau.de/news/geschlechterunterschiede-in-der-medizin-schlimmstenfalls-geht-es-um-leben-und-tod-1246109.html, 01.03.2026
[2] https://www.quarks.de/gesundheit/medizin/gender-health-gap/, 01.03.2026
[3] https://www.bundesstiftung-gleichstellung.de/wissen/themenfelder/geschlechtersensible-medizin/Geschlechtersensible Medizin - Bundesstiftung Gleichstellung, 01.03.2026
[4] https://doi.org/10.33548/SCIENTIA1277, 04.03.2026
[5] Costello JT, Bieuzen F, Bleakley CM. Where are all the female participants in Sports and Exercise Medicine research? Eur J Sport Sci. 2014;14(8):847–851.
[6] Mauvais-Jarvis F, Bairey Merz N, Barnes PJ, Brinton RD, Carrero J-J, DeMeo DL, Vries GJ de, Epperson CN, Govindan R, Klein SL, et al. Sex and gender: modifiers of health, disease, and medicine. Lancet. 2020;396(10250):565–582.
[7] https://www.linkedin.com/pulse/gender-bias-der-medizin-warum-gleiche-versorgung-ohne-lohr-d39fe/, 01.03.2026
[8] https://www.heise.de/hintergrund/Gender-Health-Gap-Es-fehlt-an-Grundlagenforschung-10307808.html, 01.03.2026
[9] https://www.bmftr.bund.de/SharedDocs/Bekanntmachungen/DE/2024/07/2024-07-12-Bekanntmachung-Gender-Health-Gap.html, 01.03.2026
[10] https://www.aekb.de/aktuelles/detail/gendermedizin-im-medizinstudium-verankern, 01.03.2026