Regenerative medicine holds extraordinary promise for transforming the treatment of chronic and life-threatening diseases. Yet the field continues to advance on an incomplete scientific foundation: the underrepresentation of women and non-binary people in both preclinical and clinical research. This is not a minor oversight, but a fundamental limitation that compromises the safety, accuracy and translational potential of emerging therapies.

Cardiovascular disease (CVD), the leading cause of death worldwide, highlights the extent of this gap. Despite well-documented sex differences in CVD prevalence, symptoms and biology, women make up about 41% of participants in CVD clinical trials overall, but only 18–20% in CVD regenerative-medicine trials, according to a 2021 analysis¹ by my colleagues and I. This means that research findings might not apply equally to everyone, and perpetuates the notion that women are simply ‘small men’. Self-identified non-binary people were largely missing from these studies.

As a result, women and non-binary people could miss out on potentially beneficial therapies, and safety risks could be obscured once treatments enter routine clinical practice. A structured approach, centred on recruitment, retention and rigorous sex-based reporting, is needed.

Recruitment: representation is imperative

Recruiting women and non-binary people into regenerative-medicine trials requires intentional design and implementation rather than passive inclusion. Barriers such as underdiagnosis and limited awareness of sex-specific disease manifestations among sponsors and clinical investigators contribute to low enrolment. It was only ten years ago that differences in heart-attack symptoms between men and women were broadly recognized in the medical community.

These barriers are not insurmountable; they are structural and solvable. Increasing the number of women and non-binary investigators and leaders in regenerative medicine is crucial. Studies show that women-led teams enrol more women, ask more inclusive research questions and prioritize outcomes relevant to diverse populations². Representation in leadership shapes representation in science.

Retention: participation must be sustained

Recruitment alone is insufficient if women and non-binary people do not remain in studies long enough for meaningful analysis. Research has shown that women withdraw from clinical trials at higher rates than men, often due to societal pressures such as care-giving responsibilities³. These factors distort the data in ways that disproportionately obscure women’s responses to therapy.

Retention challenges also affect the workforce. Female faculty members leave academia at higher rates than male colleagues at every career stage, including after obtaining tenure. Workplace issues, such as harassment, discrimination and dysfunctional leadership, have been cited as the primary driver for women leaving or considering leaving⁴.

Report: make sex-specific outcomes visible

One of the most striking indicators of systemic bias is the lack of disaggregated reporting by sex and gender. Only 4% of CVD randomized clinical trials report sex-disaggregated outcomes, despite 98% including sex or gender in participant descriptions — a stunning gap between data collected and data analysed⁵. In regenerative medicine, it is worse. In 2024, fewer than 2% of regenerative-medicine CVD studies on clinicaltrials.gov reported outcomes by sex or gender.

Our 2021 analysis revealed that female participants in a trial for autologous cardiovascular cell therapy, which uses a patient’s own cells to repair cardiac structure and function, experienced significantly lower rates of stroke, heart attack and death, compared with the placebo group. Men showed no such benefit. Without sex-specific analysis, this would have remained undetected, delaying clinical approval and limiting access to potentially life-saving interventions.