The Balance Initiative: End the Research Gap

Intro: For decades, women have been left behind in medical research. From lab experiments to clinical trials, half the population’s health needs were long an afterthought. It’s time to end this inequity. We urge our leaders and health agencies to close the gender gap in government-funded clinical trials –because when research is balanced, everyone benefits.

Historical Exclusion of Women from Clinical Trials: 

Women’s under representation in research didn’t happen by accident – it was policy. In 1977, the FDA explicitly advised excluding “any child bearing aged woman capable of becoming pregnant” from early drug trials . This rule, born of thalidomide-era fears, barred women of childbearing age from Phase I and II studies, even if they used contraception . In practice, it meant that for years virtually all early-stage trials were men-only. By the 1980s, leaders began to recognize the harm: a federal task force in 1985 warned that excluding women was detrimental to women’s health . Yet, old habits persisted –even as late as 1990, women were still intentionally kept out of most medical research, with fundamental biological differences ignored .

Progress Since 1993 – and Remaining Gaps

Change finally came in the early 1990s. In 1993, Congress passed the NIH Revitalization Act, a historic law mandating that women and minorities must be included in all NIH-funded clinical research . It required that trial data be analyzed for sex differences (at least in Phase III trials) and established offices to monitor compliance . The FDA also rescinded its 1977 ban in 1993, encouraging women’s
participation in early phases and requiring their inclusion in late-phase studies . Thanks to these reforms and advocacy by groups like the Society for Women’s Health Research, women are now routinely included in clinical trials.

Things have improved. Before 1993, women in trials were a rarity; today, women often make up close to half of study participants. 

Major initiatives – from the Women’s Health Initiative in the 1990s to the NIH’s 2016 “Sex as a Biological Variable” policy – have pushed researchers to consider sex differences in study design.

In 2024, even the White House launched a new “Advancing Women’s Health Research” initiative to boost funding and “get women the answers they need about their health” .

These are steps in the right direction.

Yet, the gap is far from closed. Women remain under-enrolled and under-studied in many areas of research. Simply being “included” isn’t enough – equitable representation is the goal, and we’re not there. Even now, women are only about 41% of participants in many clinical trials, on average . In too many studies, results aren’t analyzed by sex at all, obscuring differences between men and women. Below, we highlight some of the most glaring disparities that persist today.

Current Disparities in Medical Research:

Early-Phase Trials (Phase I/II):

The legacy of exclusion still echoes in Phase I studies. Women are often vastly underrepresented in early safety trials – only about 29–34% of participants in Phase I trials are female.  In fact, many early trials still enroll no women at all, due to overcautious
protocols. This means new drugs are often optimized on male bodies first.

Cardiovascular Disease & Stroke:

 Heart disease and stroke affect women and men in equal measure, yet research does not reflect this. In recent cardiovascular trials, women made up only~41% of participants . In stroke trials, an analysis of 30 years of studies found women were just 37.4% of participants, even though ~48% of stroke patients are women . Three-quarters of stroke studies enrolled fewer women than expected for the disease population . This
imbalance makes it harder to know if new heart and stroke treatments truly work for women.

Psychiatric Disorders:

Women suffer mental health conditions at high rates – for example, ~60% of patients with psychiatric disorders are women. But you wouldn’t know that from clinical trials: only~42% of participants in psychiatry trials are female . Despite depression, anxiety, and PTSD
often affecting women more, trials remain skewed towards men, risking therapies that don’t account
for sex-specific responses.

Other Fields:

The pattern repeats elsewhere. A comprehensive review of 20,000+ trials found that women’s representation was lowest (relative to disease prevalence) in fields like oncology, neurology, immunology, and nephrology . Even in studies of diseases that disproportionately
affect women (migraines, autoimmune disorders, etc.), research funding and participation lag behind. Clearly, these gaps are systemic, not isolated.

Lack of Sex-Specific Analysis:

It’s not just who is enrolled – it’s what we do with the data.  Alarmingly,74% of clinical trials do not report outcomes by sex . Many studies mix male and female results together without any breakdown. This “abysmal aggregation” hides crucial insights – for example, if a drug works better in one sex or causes more side effects in the other.  Failing to analyze sex differences means missing chances to improve care for both women and men.

Ignoring Hormones and Life Stages in Research Design:

Including women in studies is only part of the battle.  We also need to treat women’s physiology as afundamental part of research – not an inconvenience. Too often, clinical trials today ignore hormone-related variables like menstrual cycles, pregnancy, menopause status, or use of hormone therapy.  Many researchers still design studies as if a woman’s hormone fluctuations are a “problem” to be avoided, rather than an important factor to investigate.

Menstrual Cycle: Shockingly, even in recent landmark studies, menstrual health is an afterthought. During the COVID-19 vaccine trials, thousands of women volunteered – but researchers did not track menstrual changes . Only after vaccines were rolled out did women publicly report changes in their cycles, spurring separate studies to confirm a link . This reactive approach led to misinformation and fear (rumors about vaccines and fertility) that could have been avoided by proactive research.  It’s a clear example of how failing to consider the menstrual cycle in study design harms public trust and women’s health.

Menopause & Hormone Therapy: Women’s life stages matter. Menopause, for instance, affects half the population – yet it remains drastically under-studied . Key questions about how treatments work in premenopausal vs. postmenopausal bodies, or how hormone replacement therapy (HRT)influences outcomes, are often left unanswered. Clinical trials rarely stratify or report results by menopausal status. By omitting these variables, researchers risk overlooking differences in efficacy or side effects in women who are older or on hormone treatments.

Pregnancy and Fertility: (We recognize that protecting unborn children is essential, but) the blanket exclusion of pregnant women from virtually all trials means we lack evidence on medication safety for them. Even women who might get pregnant are sometimes steered away from studies. Modern science can do better: with proper precautions, we can ethically include pregnant or breastfeeding
women in research when appropriate, or at least study effects separately. Women deserve data
that speaks to all stages of life.

In short, women’s biology is still treated as a “confounding factor” to be controlled, instead of a core
focus. This must change. Research protocols should incorporate female-specific factors upfront – not sweep them under the rug. Without hormone-informed research, we end up with one-size-fits-all medicine that fits no one perfectly.

Why Equitable Research Benefits Everyone:Ensuring women are fully represented in research isn’t just fair – it’s smart science. Equitable research leads to better health outcomes for all genders. When studies overlook women, everyone loses.

Safer, More Effective Treatments:

History has shown the dangers of male-only data. In the late 1990s, 8 of the 10 drugs withdrawn from the U.S. market were found to pose greater health risks for women . Why? Because their side effects in women weren’t understood until too late. In general, women experience nearly twice the rate of adverse drug reactions compared to men – in part because dosing and safety margins were based on trials in men. Inclusive trials could catch these issues early, allowing drugs to be dosed or formulated appropriately for women (and
saving companies from costly post-market failures).

Medical Breakthroughs:

Studying sex differences opens new avenues for innovation.  For example,recognizing that women’s heart attack symptoms differ from men’s has led to better diagnostics for everyone.  Research on women’s unique immune responses (seen in vaccine studies and COVID-19
outcomes) gives insights that can spur tailored treatments – such as adjusting vaccine dosing or timing for maximum efficacy. When we invest in women’s health research (e.g. the study of high-risk genes in breast cancer), it pays off with knowledge that improves prevention and care . Good science acknowledges diversity – and drives discoveries that make healthcare more precise for all
patients.

Public Health and Trust: Ensuring trials reflect the real world builds trust in medicine. Women shouldn’t have to wonder if a new drug “was only tested on men” or if guidelines apply to them. When half the population sees themselves represented in research, they can have confidence that
medical advice is truly evidence-based for them. This boosts public confidence in health measures (like vaccines or medications) and reduces the spread of myths and misinformation that thrive in data gaps.

Ultimately, inclusivity in research is not a women’s issue – it is a human issue. A clinical trial that represents all of us yields findings that benefit all of us. By closing the gender gap in research, we get more reliable science, fewer dangerous blind spots, and healthier outcomes for everyone.

Call to Action: Demanding Fairness, Funding, and Accountability
We have come a long way since the days of outright exclusion, but incremental progress is not enough.  It’s unacceptable that in 2025 we still have to ask for equal representation in studies that determine our health treatments. We, the supporters of The Balance Initiative, demand bold, immediate action to end the research gap once and for all.

We call on the National Institutes of Health (NIH), the U.S. Congress, the Food and Drug
Administration (FDA), and all government health agencies to take the following actions:

Achieve Funding Parity for Women’s Health Research: Allocate research funding in proportion to
disease burden in women. Conditions that primarily or disproportionately affect women – from
menopause and endometriosis to autoimmune disorders and maternal health – must receive
equal priority and resources. No more neglecting diseases that impact women’s lives. We demand
dedicated grants and budget increases to close the funding gap for women’s health research.

Mandate Representative Clinical Trials: Enforce mandatory inclusion of women (and other
underrepresented groups) in all government-funded and industry clinical trials. It’s time to move
beyond “encouragement” to requirement. Regulators should refuse approval or funding for trials
that unjustifiably exclude women. Early-phase studies must include women by default – with
appropriate safeguards – instead of automatically defaulting to male-only data. Diversity criteria
should be a threshold for trial approval.

Require Sex-Stratified Data Analysis: Make it standard practice that all clinical trials report results
by sex. We urge NIH and FDA to require a sex-based analysis plan in every study protocol – and to
reject or invalidate studies that only publish aggregated results. Every drug, device, or therapy
seeking approval should have to demonstrate if there are sex differences in safety or efficacy.
Transparency in data is non-negotiable: publish the gender breakdown of trial participants and
outcomes so doctors and patients can make informed decisions.

Incorporate Hormone & Life-Stage Factors: Develop guidelines for hormone-informed research.
This means clinical trials should, whenever relevant, account for menstrual cycle phases, hormonal
contraceptives, pregnancy/postpartum status, and menopausal status in their design and analysis.
For example, trials could stratify female participants by whether they are pre- or post-menopause, or
collect data on menstrual changes during the study. Rather than excluding women for “complexity,”
science must embrace complexity to yield better insights. Government agencies should fund and
incentivize studies that explore how hormonal factors influence outcomes – because this knowledge
will lead to more effective, personalized treatments.

Improve Accountability and Enforcement: It’s not enough to have policies on paper. We demand
robust oversight to ensure these changes take hold. Congress and federal agencies should
strengthen the Office of Research on Women’s Health and the FDA Office of Women’s Health, giving
them power to audit trials for compliance and impose penalties or grant conditions for non-
compliance. Regular public reports should be issued on the state of women’s inclusion in research –
to track progress and highlight remaining gaps. Accountability measures (including possibly tying
funding to inclusive practices) will make sure this issue isn’t ignored

Champion Cultural Change in Research: Finally, we call for a cultural shift backed by policy. NIH
and academic institutions should train and require researchers to consider sex and gender from
the outset of every project. Institutional review boards (IRBs) and grant reviewers must flag protocols
that sideline women’s health variables. It should become second nature in science that sex
differences are a fundamental aspect of good research design, not an optional add-on. Leaders
at the NIH and CDC should publicly champion the message that women’s inclusion strengthens
science – making it clear that the old excuses (“women are too variable,” “what if they get
pregnant?”) are no longer acceptable.

Signatures & Support – Together, Let’s End the Research Gap:

We, the undersigned, firmly believe that health equity is within reach. The problems outlined above are not intractable – they are man-made, and we have the power to fix them with man and woman power. By signing this petition, you are standing up for fairness in research and better health outcomes for all. It’s time to balance the scales. Medical research should never again treat women as second-class citizens. We must ensure that every clinical trial, every breakthrough, and every guideline is informed by data from both women and men, analyzed with an eye to differences, and designed to serve everyone’s needs.

Our mothers, daughters, sisters – and yes, our fathers and sons too – all deserve medical evidence that is accurate and applicable.  No more knowledge gaps.  No more one-size-fits-all medicine that fits only half the population.

Join The Balance Initiative and demand an end to the research gap. Together, we can create a future
where medical research is truly representative, responsive, and just. When we ensure women are fully
counted, studied, and heard in science, we uplift the health of all humanity.  Let’s make clinical equity the new standard. Let’s make sure the next generation of cures and treatments are proven effective for everyone. By uniting our voices, we will send a clear message to NIH, Congress, and all our leaders: the time for half-measures is over – we need full equality in research now.

Sign this petition and help secure a healthier, fairer future for women – and for us all. Together, we will end the research gap!

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https://swhr.org/about/1977-1989-timeline/
History of Women’s Participation in Clinical Research
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1990-1999 Timeline - Society for Women's Health Research
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Does the Gender Gap in Medical Research Still Exist? | TIME
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Women in clinical trials - MVA
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Not including enough women in stroke trials could be impacting their treatment | The George
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Menstruation Is an Afterthought in Research. Here’s Why That Needs To Change - Ms. Magazine
https://msmagazine.com/2023/01/23/menstruation-clinical-trials-research-women-periods-covid