Have you ever wondered why so many treatments seem “one‑size‑fits‑all,” only to work differently in half the people? Women remain underrepresented in research, even in 2025. This post uncovers the hidden bias built into science and why it matters to you.
1. A Legacy of Exclusion: The Story Behind the Bias
Looking back, women were largely excluded from medical research, especially from the 1950s through the early 2000s. Women of childbearing age were routinely left out of trials to avoid the perceived risk to unborn children (as seen after the thalidomide disaster). Even treatments mainly used by women, like hormone replacement therapy, were first tested on men, making women the afterthought in their healthcare narrative LinkedIn+1TIME+1.
Despite landmark legislation like the NIH Revitalization Act of 1993, which mandated inclusion of women and minorities in NIH‑funded clinical trials, real change was slow to arrive. And for decades, male animals remained the default in preclinical research (due in part to researchers worrying about female hormonal variability) orwh.od.nih.gov+2swhr.org+2LinkedIn+2.
2. Preclinical Research Are Still Male‑Dominated in 2025
Recent studies show that 84% of animal studies still rely solely on male rodents, with only about 16% including female models. Shockingly, even in diseases that affect women more, like autoimmune disorders, 88% of preclinical work used male animals exclusively Pharma’s Almanac.
In heart‑disease research a field where women are the leading victims—nearly 72% of studies used only male animals, and only 15.5% included both sexes. Even more concerning: only 35% of studies reported any results by sex, meaning outcomes were not analyzed separately for women and men Reddit+3AHA Journals+3Pharma’s Almanac+3.
3. Clinical Trials Still Don’t Mirror Real‑World Reality
Even when women are enrolled, they are often underrepresented or not analyzed by sex:
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In cardiovascular trials, although women are about 49% of patients, they made up only 41.9% of trial participants TIMETIME+2TechTarget+2Alcimed+2.
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In oncology, women comprise 51% of patients but represent only 41% of participants in drug trials TechTarget.
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For psychiatric disorders, women make up 60% of patients but only 42% of clinical trial participants orwh.od.nih.gov+15TechTarget+15TIME+15.
Meta‑analyses show that Phase I drug trials include only 29–34% women; Phase II around 41–51%; Phase III 38–49% still lagging behind the actual disease burden Alcimed.
Device trials are no better: a 2024 JAMA review found that only about 29% of cardiovascular device trials included women; the overall average was just a third of participants JAMA Network.
4. Even Trial Leadership Is Biased
It’s not just study subjects, the researchers themselves reflect gender disparity. In randomized controlled trials between 2011 and 2020, only 30% of lead (first) authors were women, even as women authors accounted for just 12–15% of senior authorship roles Healio. Fewer female leaders may influence both research priorities and inclusivity at every stage.
5. Why Does This Still Matter in 2025?
🔸 Misdiagnoses & Delayed Care
Women’s symptoms, especially for diseases like heart attack, stroke, depression, Alzheimer’s, often differ from men’s. When research overlooks these differences, diagnoses are delayed, and treatments miss the mark.
🔸 Adverse Drug Reactions
Women are nearly twice as likely as men to experience adverse drug reactions. That’s because dosing standards are based on male metabolism, ignoring how women absorb, distribute, and eliminate drugs differently arXivLinkedIn.
🔸 Inequitable Innovation
Conditions like endometriosis, menopause symptoms, and certain autoimmune disorders remain understudied. Despite women making up 80% of autoimmune disease cases, research investment in female‑specific presentation lags.
A Reddit-sourced analysis found:
“Only 1% of healthcare research…was dedicated to female‑specific conditions beyond oncology…Just 4% of all biopharma R&D spending goes toward female‑specific conditions…In 75% of cases where a disease affects one gender, research funding favors men.” LinkedInReddit
6. Policy Progress and the Gaps That Remain
✅ NIH’s Sex as a Biological Variable (SABV) policy, launched in 2016, mandates consideration of sex in NIH-funded research. But only about 42% of studies that include both sexes separate results by sex, and that figure may be declining over time swhr.orgpubmed.ncbi.nlm.nih.govorwh.od.nih.gov.
✅ The EU, Canada, and other agencies have adopted similar guidelines. But implementation remains inconsistent, and many trials still exclude pregnant or breastfeeding women entirely orwh.od.nih.govWikipedia.
✅ In the UK, data from 2019–2023 show that male‑only trials outnumber female‑only trials by 67%. Worse, only 3.7% of trials were female‑only, while barely 1.1% involved pregnant women and 0.6% breastfeeding women, theguardian.com.
Still, steps are being taken: in the US, President Biden signed an executive order to improve women’s health research and data collection, boosting NIH funding and spotlighting conditions like Alzheimer’s and heart disease TechTarget+2AP News+2LinkedIn+2.
7. What Can Be Done (and What You Can Do)
🔍 For Researchers & Institutions:
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Design studies with sex‑balanced participation.
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Analyze and report outcomes by sex explicitly.
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Engage women participants and advocates in trial design.
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Fund and publish female-only studies where relevant.
🧭 For Readers & Advocates:
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Ask whether doctors know if trials included women.
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Support groups and calls for transparency in clinical research.
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Share articles and advocate for inclusion in research, especially female usability and safety data.
Women are nearly half the world’s population (49.6%) and yet remain underrepresented in many arenas of clinical and preclinical research—from lab models to trial leadership to funding priorities wifitalents.com+14Alcimed+14Wikipedia+14Wikipedia+3orwh.od.nih.gov+3Wikipedia+3TIME+2theguardian.com+2swhr.org+2Healio+1TIME+1.
Bridging this gap matters because health decisions, drug safety, and treatment effectiveness affect real lives every day. When science treats half the population as an afterthought, it fails us all.
To Summarize:
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Women are still underrepresented in preclinical and clinical research in 2025.
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Male bias persists in animal studies (~84%) and clinical trials (~41–48% female participation).
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Female‐only and pregnant participants are almost absent.
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Adverse drug reactions are more common in women due to male-based testing.
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SABV policy exists, but sex‑based analysis and female leadership still lag.
📢 Let’s push for inclusive science that recognizes sex differences, funds female-specific studies, and shares data transparently. Women’s bodies deserve equal attention in research because we deserve better health outcomes.
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