Sex and Gender Reporting in Medical Manuscripts: What the SAGER Guidelines Require in 2026

When the Sex and Gender Equity in Research guidelines were published in May 2016 by the European Association of Science Editors (EASE) and the Gender and Health Research Network (GENDRO), most medical journals treated them as voluntary good practice. The guidelines addressed a real problem, the systematic exclusion of women from clinical trials and the pooling of sex-disaggregated data in ways that obscured meaningful biological differences, but enforcement was sparse and compliance was left to individual authors to negotiate with editors at their own discretion.

A decade later, the picture has changed enough to require authors to pay closer attention. The SAGER@10 campaign running through the end of 2026 aims to secure adoption by 100 leading journals and 15 publishers while reaching 2 million accesses to the guidelines documentation. Roughly 1,711 peer-reviewed journals have formally adopted the guidelines as of early 2026. Nature Portfolio made sex and gender reporting requirements mandatory starting in June 2022. The Lancet family developed its own compliance checklist that editorial teams use during initial screening. WHO adopted the SAGER framework for its own research publications. And a 2026 study published in Communications Medicine found that among NIH R01-funded papers that included both male and female participants, fewer than 44 percent actually conducted sex-disaggregated analyses.

That last number captures the central problem. Enrolling both sexes is not the same as analyzing outcomes by sex. Many authors understand they are supposed to include women in their studies, but have not adjusted their analysis and reporting practices to match. That gap is where reviewers now push back, and in journals with strict SAGER requirements, it can stop a submission before it reaches peer review.

Why the Evidence Gap Persisted for So Long

The historical exclusion of women from medical research was rarely ideological in any direct sense. It was practical, or seemed so at the time. Regulatory agencies, particularly the US FDA before its 1993 guideline reversal, discouraged or restricted the inclusion of women of childbearing potential in early-phase trials on the grounds that hormonal variability would complicate safety signals and that teratogenic risk made inclusion ethically complex. Those restrictions produced a literature skewed toward male-centered evidence, and once that literature became the foundation for clinical guidelines and textbook knowledge, the skew self-propagated.

Cardiovascular medicine offers the most documented example. Landmark trials that shaped heart failure management, such as the SOLVD and V-HeFT studies from the 1980s and early 1990s, enrolled populations that were 80 to 90 percent male. The treatment protocols that followed were derived primarily from those samples. Women with heart failure, who are more likely to present with preserved ejection fraction and different symptom profiles, were treated with evidence that was not generated from data that looked like them.

The problem was not unique to cardiology. Pharmacology studies have shown that adverse drug reactions are reported at substantially higher rates in women for multiple drug classes, in part because dose approvals were calculated from male-dominated safety data. Autoimmune conditions, which disproportionately affect women, were studied in ways that did not reliably capture sex-related patterns in disease progression or treatment response.

SAGER was designed to address this from the reporting end, operating on the logic that if journals required sex and gender to be reported transparently, authors would have to think about it explicitly in their design. The assumption proved partially correct. Transparency improved. Analytical practices improved more slowly.

What the SAGER Guidelines Actually Require

The SAGER guidelines address four phases of a research project: study design, data collection and analysis, abstract reporting, and full manuscript reporting. The four core requirements, as reflected in Nature Portfolio's updated instructions and the Lancet's checklist, can be summarized as distinct obligations at each stage.

At the design and methods stage, authors must state whether sex and gender were considered when the study was designed, describe how they were defined and measured, and explain any decisions to exclude one group. This applies to studies with human participants, vertebrate animals, and cell lines. For human studies, this means specifying how sex was categorized (biological sex as recorded in medical records, self-reported sex, or self-reported gender identity) and noting which variable the analysis uses. For animal studies, this means reporting the sex composition of the sample and, where only one sex was studied, providing a scientific rationale.

At the analysis stage, if no sex- or gender-disaggregated analysis was conducted, the guidelines require that this be stated explicitly with a justification. At most journals that enforce SAGER, the justification needs to be scientific rather than logistical. Insufficient sample size to detect differences is a recognized constraint, but it should be stated as such, with the relevant descriptive statistics still presented by sex rather than suppressed entirely.

In the abstract, if a study's findings apply primarily or only to one sex, that scope must appear in the abstract itself, not just buried in the discussion. A reader skimming a cardiovascular meta-analysis should be able to tell from the abstract whether the pooled results are generalizable to both sexes.

In the body of the paper, results should be reported disaggregated by sex or gender where the data allow. Cell line studies should identify the sex origin of the cell lines used, because cell line behavior can differ by sex in relevant ways, particularly in oncology and immunology research.

Sex and Gender Are Not Interchangeable, and Journals Know It

One of the more reliable ways to draw an editorial flag is to use "sex" and "gender" as synonyms throughout a manuscript. These terms refer to different constructs in biomedical research, and journals with SAGER policies expect authors to use them with deliberate precision.

Sex, in the SAGER framework, refers to biological attributes: chromosomal makeup, hormonal environment, gonadal function, and other physiological characteristics. It is generally treated as a categorical variable, though the guidelines acknowledge that biological sex exists on a spectrum and intersex conditions are real. Gender refers to the socially constructed roles, identities, expressions, and expectations that vary across cultures and individuals. Gender is not equivalent to sex, and the two do not always align.

The practical relevance of this distinction depends on what your study is measuring. A pharmacokinetics study is primarily concerned with biological sex because drug metabolism is influenced by hormonal environment, body composition, and enzymatic activity that differs between sexes. A study of treatment adherence, care-seeking behavior, or symptom self-reporting is more appropriately analyzed through gender, because social factors shape how people interact with the healthcare system in ways that do not map cleanly onto biological sex.

Many datasets, especially administrative health records, record sex at birth rather than current gender identity. That is a legitimate data constraint, and the right response is to acknowledge it. If your paper uses administrative sex as a proxy and does not capture gender identity, say so in the methods and note it as a limitation. Reviewers at journals with SAGER requirements will look for this kind of transparency.

Which Journals Require SAGER-Aligned Reporting in 2026

The enforcement landscape is uneven, but the direction of travel is consistent. More journals are formalizing requirements that were previously recommendations, and several flagship publishers now treat missing sex and gender information as a reason to return a manuscript before external review.

Nature Portfolio journals (including Nature, Nature Medicine, Nature Cancer, Nature Communications, and Nature Metabolism) have made the most explicit changes. Their updated author guidance, introduced in 2022 and maintained since, requires authors to answer four specific questions about how sex and gender were handled. These questions cover study design, justification for any single-sex approach, abstract scope, and data disaggregation. Papers that do not address these questions may be returned without external review. The requirements apply to studies involving human participants, vertebrate animals, and cell lines.

The Lancet family developed a standalone SAGER checklist that editors use during initial screening. Authors submitting to The Lancet, eClinicalMedicine, The Lancet Digital Health, and related titles should expect this checklist to be part of the submission process. The Lancet was among the early adopters of the guidelines and has been involved in their development and promotion through the GENDRO network.

BMJ has published guidance encouraging sex-disaggregated reporting and includes sex and gender considerations within its statistical analysis expectations and research integrity materials. JAMA publications embed similar expectations within their methodological standards rather than a standalone checklist. WHO adopted the SAGER guidelines for its own research outputs, setting a precedent for how international health research should handle this reporting category.

For journals without a formal SAGER policy, the guidelines still shape reviewer expectations. Peer reviewers at most major medical journals have seen this reporting standard discussed enough that its absence is noticeable. Even where it will not trigger a desk rejection, a manuscript that fails to describe how sex and gender were handled is likely to receive a revision request asking for that information.

The NIH SABV Policy and Its Present Status

For researchers working under NIH funding, the sex as a biological variable (SABV) policy adds a parallel requirement. Established by NIH in 2016, the policy requires that applicants for funded research in humans and vertebrate animals factor sex as a biological variable into their study designs, analyses, and reporting, or provide a scientific justification for a single-sex study. The SABV policy applies to preclinical research as well as clinical, which means it reaches work that might otherwise not be subject to the clinical reporting standards journals typically enforce.

In early 2025, the NIH website pages describing the SABV policy and its implementation guidance were taken down as part of broader federal actions under the new administration. Those pages included practical documentation that researchers had relied on when writing grant applications and structuring study plans. A legal settlement announced in September 2025 required the Department of Health and Human Services to restore certain webpages, and some of this content has been made accessible again. The situation reflects genuine policy uncertainty at the federal level.

What has not changed is the underlying scientific rationale, and the independent journal requirements that do not depend on NIH guidance. Authors should treat the journal's instructions as the operative standard when preparing manuscripts. Whether or not a particular NIH web page is currently accessible, Nature Portfolio and the Lancet family are still enforcing their own sex and gender reporting requirements. Authors with NIH-funded research should also document how they addressed SABV in their study protocols, independent of any shifts in the federal guidance landscape.

Where This Reporting Goes in the Manuscript

Sex and gender reporting is not a single paragraph that gets dropped into the discussion. It threads through multiple sections of the paper, and missing it in even one section creates the impression of incomplete compliance.

In the methods section, describe whether sex and gender were considered in the study design, how they were defined, and how they were measured or collected. If you used a self-report instrument, note what categories it offered. If you used administrative records, note what sex variable those records capture and how it was validated. If your study enrolled only one sex, provide the scientific rationale here. This is not the place for vague language like "sex was recorded as part of demographic data." Be specific.

In the results section, present outcomes disaggregated by sex or gender where the data allow. If your sample was too small for a formal sex-stratified analysis, report the descriptive statistics by group anyway and note the sample size limitation. Presenting these numbers does not commit you to claiming a significant sex-based difference. It gives readers the information they need to draw their own inferences.

In the abstract, reflect the sex composition of your sample, and if the findings are limited to one sex, say so in the abstract rather than only in the discussion. Readers who see the abstract only, which is most readers, deserve to know the scope of the study population.

In the limitations, note any residual concerns: binary categorization of a non-binary construct, reliance on administrative sex data as a proxy for gender, unmeasured confounding of biological and social factors, or inadequate statistical power for sex-based subgroup analyses.

The Compliance Gap in Clinical Research

The Communications Medicine study published in 2026 examining sex reporting in NIH R01-funded research found patterns that help explain why this issue keeps generating revision requests even among well-prepared teams. About 61 percent of studies in the sample included both sexes. Among those that did, only 44 percent conducted sex-based analyses. That gap between inclusion and analysis suggests the change in enrollment practices has outpaced the change in analytical practices.

Part of this may be planning. If a study was designed with a primary endpoint that is pooled across sexes, a post-hoc sex-disaggregated analysis is statistically weaker and harder to defend. This is an argument for building sex-stratified analyses into the pre-specified statistical analysis plan before data collection begins, not after. It is also an argument for powering studies to detect sex-based differences if the research question warrants it.

For authors with already-collected data, the answer is to present what you have honestly. If the sample is underpowered for sex-stratified comparisons, say so, present the descriptive data by sex, and frame the sex analysis as exploratory or hypothesis-generating rather than confirmatory. That is better science than presenting only the pooled result as though sex were irrelevant, and it is what journals with SAGER requirements will be looking for.

What Happens When This Reporting Is Missing

At journals with formal SAGER requirements, the consequences of missing sex and gender reporting vary by journal and by how early the gap is detected. Nature Portfolio journals may return a manuscript before external review if the required sex and gender questions are not addressed, meaning the paper goes back to the authors without any peer review feedback. This is a slower form of desk rejection: it does not formally reject the paper, but it adds a revision round that could have been avoided with correct initial preparation.

At journals with softer policies, missing sex and gender reporting is more likely to surface as a peer reviewer comment. Reviewers who are familiar with the SAGER framework, or who simply work in a field where sex differences are scientifically relevant, will ask why the analysis is pooled, whether sex-stratified data can be presented, and how sex was defined. That comment can feel unexpected if the authors had not planned for it, and responding to it under revision deadline pressure is genuinely harder than getting the analysis right before submission.

The most practical approach is to treat sex and gender as a dimension of the study that needs to be documented from the beginning, alongside sample size calculations, outcome definitions, and statistical analysis plans. Authors who think about this early, before the study is complete rather than when the paper is at draft stage, have the most options for how to handle it. Authors who encounter it for the first time in a reviewer comment are working with constraints.

A Practical Way to Get Ready Before You Submit

The SAGER guidelines, like most reporting frameworks, are more useful when you treat them as a structured question to answer rather than a box to check. The underlying question is: did you think carefully about how sex and gender affect this research, and did you tell readers what you found out? Most of the reporting requirements follow from that question naturally.

Before submitting, look up the target journal's current sex and gender reporting policy. For Nature Portfolio titles, this is described in their editorial policies section and in the submission guidance for each journal. For Lancet journals, the SAGER checklist may be downloadable or linked from the instructions for authors. For other journals, a search of the author instructions for the terms "sex," "gender," and "SAGER" will usually surface any specific requirements.

If the journal has no policy, draft your sex and gender reporting section as though it did. Describe how sex was defined and measured, present outcomes by sex where your data allow, note any limitations in how the data were collected, and flag in the abstract if the findings are limited in scope. That practice will not hurt your chances at journals with no policy, and it will save a revision round at journals that do have one.

Why This Matters Beyond Compliance

There is a version of this discussion that treats SAGER reporting as an administrative requirement, an extra checklist item that journals started requiring and that authors now have to navigate before they can get to the real business of publication. That framing misses what the guidelines are actually for.

The research literature still contains studies, some of them foundational to clinical practice, whose findings may not apply uniformly across sexes and genders in ways that the original authors never tested and readers cannot detect. That is a genuine problem for patients, and particularly for patients in underrepresented groups who have historically been under-enrolled. When a clinical guideline is built on evidence that is implicitly sex-specific but not labeled as such, the patients who bear the cost are the ones who were not adequately represented in the studies.

This is what SAGER is trying to fix at the reporting level. Authors who engage with it seriously, rather than treating it as bureaucratic overhead, are contributing to a more reliable and broadly applicable clinical evidence base. The practical implication for your next manuscript is simply to plan sex and gender reporting before you start writing the methods, and to check the target journal's requirements before you finalize the submission package. The investment is small. The return, in avoided revision cycles and in the quality of what you contribute to the literature, is real.

Further Reading