International Women’s Day: 34 Years of Science, Sisterhood and Twins

When I set up TwinsUK in 1992 with Tim Spector, I could not have imagined the journey ahead. What began as an ambitious idea – to build a national twin registry that could help unravel the complex interplay between genes, environment and health — became not just a research cohort, but a community. And at its heart, that community has been powered by women.

As I step down and retire this month from my role as Executive Director, I find myself reflecting not only on the science, but on the people. The women who joined our studies year after year. The women who ran operations, clinics, analysed data, managed laboratories, wrote grants, mentored students often while balancing caring responsibilities.

Building TwinsUK at King’s College London was never a solo endeavour. It required institutional belief, interdisciplinary courage, and resilience through funding cycles, evolving technologies, and shifting scientific paradigms. We moved from early genetic epidemiology to genomics, microbiome science, digital health and beyond – always asking bigger questions and refining how we answer them.

But what has remained constant is the generosity of our participants. The majority of our twin volunteers are women. Over three decades, they have given their time, their biological samples, their health histories, and their trust. Many joined as young adults and are now grandparents. Their commitment has enabled discoveries that have shaped understanding across ageing, complex disease and personalised medicine. They are not simply “subjects” of research; they are partners in it.

International Women’s Day invites us to celebrate achievement, but also to acknowledge the ecosystems that make achievement possible. At King’s, I have had the privilege of working alongside extraordinary female colleagues – Professors and professional service staff, clinicians, statisticians, nurses, project managers and PhD students – whose brilliance and integrity have strengthened every stage of this endeavour. I have watched young scientists grow into leaders. I have seen collaborations flourish across disciplines and borders. I have learned that leadership is less about direction and more about stewardship – creating the conditions in which others can thrive.

There were challenges, of course. When we began in the early 1990s, female leadership in large-scale biomedical research was far less visible than it is today. Securing long-term funding for cohort infrastructure required persistence and optimism in equal measure. Sustaining participant engagement over decades demanded creativity and care. Yet perhaps being underestimated at times was not entirely a disadvantage – it sharpened focus and fostered solidarity.

What makes me most proud is not a single paper or metric, but continuity. A cohort that has endured. A research culture that values rigour and humanity. A network of twins who feel connected not only to science but to one another.

As I retire, I do so with immense gratitude. To Tim, whose scientific vision helped spark this journey. To the leadership at King’s who believed in building long-term research infrastructure. To the funders who recognised the importance of sustained cohort science. And above all, to the thousands of women – participants and professionals alike – whose contributions have shaped not just a dataset, but a legacy.

On this International Women’s Day, I celebrate them.

Science advances through data. But it is sustained by people. And for 34 years, I have had the privilege of working among remarkable women who proved, time and again, that collaboration, curiosity and commitment can change the way we understand human health.

That has been the true gift of TwinsUK.