Despite significant advancements in science and medicine, women remain critically understudied in scientific research and face alarming rates of underdiagnosis in medical care. This problem is not just a vestige of past eras but a current, pressing issue that directly undermines the health outcomes of women worldwide. Understanding why this underrepresentation exists and how it perpetuates disparities is vital for women’s health advocates and healthcare professionals working towards equity in care.

The Underrepresentation of Women in Scientific Research

Historically, men have been the default participants in clinical and biomedical research. One major reason for this is the perceived "complexity" that female physiology adds to study design, primarily due to factors such as hormonal fluctuations, menstrual cycles, pregnancy potential, and other sex-specific variables. These variances were often seen as confounding factors; thus, researchers excluded women to reduce variability and simplify data analysis.

Hormonal Variance and Exclusion from Trials

Women experience cyclical changes in hormone levels throughout their lives, from puberty through menopause, which can affect pharmacodynamics and pharmacokinetics. For example, estrogen and progesterone variations influence how drugs are absorbed, metabolized, and excreted. Instead of designing studies that account for these biological realities, many researchers historically excluded women altogether.

Crucially, the consequences of these exclusions ripple through to clinical practice. Medications, treatments, and medical devices may be tested predominantly or exclusively on male subjects, leading to recommendations, dosages, and side-effect profiles that don't align with women’s needs. This lack of female representation is not limited to drug trials but extends to almost every area of medical research, from cardiovascular studies to mental health research.

The Broader Impact on Women’s Health Products

Because women are less likely to be included as research participants, products intended specifically for women or used disproportionately by women may be inadequately tested for their unique physiology. From heart medications to medical implants, the evidence base informing their safety and efficacy in women is often thinner, resulting in suboptimal and sometimes dangerous health outcomes.

The Cascade to Underdiagnosis

The underrepresentation of women in research significantly contributes to the underdiagnosis of women in everyday clinical practice. Here’s how:

Misunderstanding Disease Presentation in Women

Symptoms of diseases often manifest differently in women compared to men. For example, heart attack symptoms in women may be less “classic”—presenting as fatigue, indigestion, or back pain, rather than the stereotypical chest pain. Because research (and, as a result, medical education) has prioritized male symptoms as the template, healthcare providers may miss or misinterpret women’s symptoms.

Diagnostic Tools Calibrated on Male Norms

Diagnostic criteria and reference values for many diseases are based primarily on male populations. This includes laboratory test thresholds, imaging interpretations, and risk assessment tools. The application of male-biased benchmarks can mean that women’s diseases are detected later, when they are more advanced and harder to treat.

Scientific Reasons Behind Underdiagnosis

Several fundamental scientific factors contribute to this systemic issue:

• Sex Differences in Disease Biology: Diseases like autoimmune disorders, osteoporosis, and certain cancers behave differently depending on sex. For instance, women are more likely to suffer from autoimmune diseases, but many studies don't disaggregate data by sex.
• Biased Study Designs: Lack of stratification by sex and failure to consider hormonal status (e.g., menstrual phase, menopause, contraceptive use) can mask critical differences between men and women.
• Systemic Gender Bias: Beyond biology, gender-related biases in research and medicine (the societal roles and expectations associated with being “female”) influence everything from funding priorities to clinical decision-making, perpetuating a cycle of inequity.

Recent Progress and Ongoing Challenges

Awareness of this bias is growing, and there have been significant calls for the inclusion of sex and gender as essential variables in scientific research (Hallam et al., 2022). Funding agencies, scientific journals, and ethical committees increasingly require that studies include women and analyze results by sex. These measures are helping to build an evidence base that acknowledges and addresses differences in disease presentation, progression, treatment, and outcomes.

However, real-world translation remains slow. Systemic barriers—including broader gender inequities in society, cultural norms, access to healthcare, and structural discrimination—continue to impede progress. Emerging research reveals that even where data on women is being collected, it is often misinterpreted or miscommunicated, with a risk of reverting to oversimplified explanations that reinforce rather than challenge patriarchal structures.

The Path Forward

For meaningful change, multidisciplinary approaches are needed. Integrating biomedical, social, and policy research can help disentangle the complex interplay between sex, gender, and health outcomes. Addressing the underrepresentation of women in trials must go hand in hand with initiatives to reduce bias in diagnosis, invest in female-driven research, and advocate for system-wide change—from funding to policy to clinical practice.

Sources