New ‘Sex and Gender Science’ Field Merges Biology and Society to Reshape Medicine

For most of modern biomedical history, the study of human difference has been split down an invisible seam. On one side sat sex, treated as a matter of chromosomes, hormones, gonads, and physiology, best examined with the tools of molecular biology, endocrinology, and neuroscience. On the other side sat gender, handled largely by sociologists, anthropologists, and public health scholars as a social construct encompassing roles, relations, identities, norms, and institutional structures. The two literatures rarely spoke to each other, and when they did, it was often with mutual suspicion about methods, assumptions, and terminology. A new perspective, published in the journal Biology of Sex Differences, argues that this division has become untenable, and that the future of rigorous health research depends on treating sex and gender as inseparable, dynamically interacting variables rather than parallel and separate domains.

The article, the product of a consensus workshop at an international meeting of the Organization for the Study of Sex Differences in May 2019 and a subsequent expert meeting in Ottawa sponsored by the Institute of Gender and Health of the Canadian Institutes of Health Research, brings together a strikingly interdisciplinary authorship. Neuroscientists, physiologists, historians of science, internists, nephrologists, nurses, social workers, epidemiologists, and implementation scientists, led by co-first authors Gillian Einstein of the University of Toronto and Louise Pilote of McGill University, along with senior author Cara Tannenbaum of the Université de Montréal, collectively propose a name and a vision for what they call Sex and Gender Science. They describe it as a transdisciplinary, integrative, bio-social-medical field that combines diverse methods to investigate how sex and gender dynamically interact to shape disease outcomes, illness experiences, and the very conduct of science itself.

The conceptual core of the proposal rests on the claim that sex and gender are interactional and deeply interwoven. Within sex, the authors situate hormonal, genetic, physiological, and morphological processes and characteristics, from chromosomal complements and gonadal steroid fluctuations to organ-level physiology and morphology. Within gender, they include roles, relations, norms, institutional imperatives, and identities, along with their downstream consequences for behavior, environment, access to resources, and exposure to stress. Crucially, the authors argue, these domains are not merely additive; they operate on each other. Gendered expectations influence hormonal and physiological responses, while biological traits shape how institutions and individuals respond to a person. In this framing, gender literally gets under the skin, while sex expresses itself inescapably through social worlds.

Concrete clinical examples illustrate the stakes. Acute coronary syndrome presents differently across patients in ways that reflect both vascular biology and gendered patterns of symptom recognition, care-seeking, and triage in emergency departments. In Alzheimer’s disease, two-thirds of affected individuals are women, and research discussed in the article points to interactions between reproductive histories, such as surgical menopause, stress physiology involving corticotropin-releasing factor, and gendered lifecourse exposures, rather than a single biological cause. In nephrology, sex differences in kidney physiology intersect with gendered differences in access to dialysis, transplantation, and medication adherence. Even occupational health reflects the interplay, as shown by analyses of personal protective equipment designed around male body norms during the COVID-19 pandemic, where ill-fitting gear compromised the safety of women in frontline roles. The authors also cite emerging concerns about automatic gender recognition technologies and gendered patterns of cannabis use disorder as domains where simplistic binary assumptions fail patients and obscure mechanisms.

Methodologically, Sex and Gender Science is defined by its refusal to choose between reductionist and constructionist approaches. The authors assume complexity, question established stereotypes and binaries, and support evolving methods that can capture interactional effects over time. That means experimental work in animal models attentive to sex as a biological variable can be paired with qualitative and quantitative human studies of gendered environments; intersectional epidemiology can be integrated with endocrine and genetic measurement; and implementation science can test whether sex- and gender-informed findings actually change clinical practice. The transdisciplinary ambition is deliberate: rather than creating another silo, the field aims to weave together the humanities, social sciences, and biomedical sciences, drawing on decades of feminist scholarship, gender studies, and basic biology that have until now developed along separate tracks.

The historical context for this synthesis is instructive. Biomedical research long treated male bodies as the default experimental subject, from clinical trials to preclinical animal studies, on the grounds that hormonal cycles made female subjects inconveniently variable. Landmark policy changes in the United States, Canada, and Europe over the past three decades required the inclusion of women in clinical research and the accounting for sex as a biological variable in grant applications. Simultaneously, scholars in gender and health demonstrated that social positions assigned by gender produce measurable health inequities, from differential exposure to violence and occupational hazards to differences in healthcare access and treatment. What was missing, the authors argue, was a systematic framework linking these two streams, so that researchers could ask not simply whether men and women differ, but how biological and social variables interact to produce particular outcomes in particular individuals.

The consensus process behind the article gives its claims unusual weight. By convening basic scientists who study sexually dimorphic neural circuits and stress pathways alongside clinicians, historians, and social scientists, the meeting produced a shared vocabulary and a shared commitment. The resulting highlights, as stated by the authors, include forging new ways of knowing about wellness, health, and disease; assuming complexity and questioning binaries; providing a more comprehensive picture of human health when sex and gender are studied together; and starting from the particularity of individuals with the ultimate goal of improving the well-being of all. That final point is significant politically as well as scientifically: the field explicitly encompasses transgender and gender-diverse populations, recognizing that gender identity itself interacts with biology in ways that mainstream medicine has historically ignored or pathologized.

For clinical practice, the implications are immediate. Diagnostic criteria, drug dosing, device design, and screening schedules built on averages derived from unrepresentative populations can be reexamined through the interactional lens that Sex and Gender Science provides. A patient is never just a sex and never just a gender; each person embodies a unique configuration of hormonal milieu, genetic background, organ physiology, gendered labor and caregiving burdens, institutional exposure, and identity. Precision medicine that ignores either domain is, on this argument, not precise at all. The authors point to the growth of national organizations, such as the Canadian Organization for Sex and Gender, and to curriculum reform in medical schools as evidence that institutional infrastructure is beginning to catch up with the science.

The article also acknowledges open questions and future directions. Measuring gender as rigorously as sex is measured remains an active methodological challenge, with validated instruments still evolving. Distinguishing interaction effects from confounding in observational data requires statistical sophistication and large, diverse cohorts. And the field must navigate political controversies surrounding sex and gender discourse without retreating from empirical evidence. The authors frame these challenges as generative rather than paralyzing, arguing that the very friction of integrating methods across disciplines produces better science, sharper questions, and more honest uncertainty. They call for funding structures, training programs, and publication venues that reward transdisciplinary work rather than penalizing it in favor of narrow, single-domain studies.

If Sex and Gender Science succeeds on its own terms, the payoff could be a medicine that finally matches the complexity of the patients it serves: one in which a heart attack, a dementia diagnosis, a kidney transplant, or a workplace injury is understood through the full entanglement of chromosomes, hormones, organs, identities, relationships, and institutions that shaped it. The article’s message to researchers is blunt in its simplicity. It is not either sex or gender; it is both, together. After decades of separation, the biological and the social are being brought back into a single scientific frame, and the authors argue that the health of everyone stands to gain from what this emerging field discovers next.

Subject of Research: Sex and Gender Science, an emerging transdisciplinary field integrating biological sex and social gender in health research

Article Title: Sex & Gender Science: integrating the social with the biological

Article References: Einstein, G., Pilote, L., De Vries, G., Richardson, S., Forger, N., Perović, M., Ahmed, S., Bauer, G., Graham, I. D., Greaves, L., Klinge, I., Logie, C. H., McKay, D., McMurtry, M. S., Oliffe, J. L., & Tannenbaum, C. (2026). Sex & Gender Science: integrating the social with the biological. Biology of Sex Differences. https://doi.org/10.1186/s13293-026-00977-8

Image Credits: AI Generated

DOI: 10.1186/s13293-026-00977-8

Keywords: sex and gender science, biological sex, gender and health, transdisciplinary research, Biology of Sex Differences, health inequities, sex differences, gender identity, precision medicine, Alzheimer's disease, cardiovascular disease, Canadian Institutes of Health Research