Study: A Decade After NIH Recommended Sex Data Reporting, Most Funded Research Still Isn’t Doing It
A review of nearly 600 NIH-funded studies published between 2017 and 2024 found that only 44% reported results broken down by sex, despite a 2016 policy requiring researchers to do so. Sixty-one percent of the studies included women, but most didn’t analyze whether outcomes differed between sexes.
The gap matters because it isn’t theoretical. Drugs are dosed, treatments are designed, and risk thresholds are set based on data that may not reflect how women respond at all.
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The NIH’s sex-as-a-biological-variable policy was introduced specifically because decades of research conducted primarily on male subjects had left medicine with significant blind spots. Drugs approved based on male-dominant trial populations were being prescribed to women at the same doses, with the same expected side effect profiles, and the same assumptions about efficacy, despite evidence that biology affects all three.
The review found that compliance with the reporting requirement varied significantly by disease category and journal. Studies in cardiovascular disease and cancer were more likely to report sex-disaggregated results. Research in neurology, psychiatry, and metabolic disorders lagged. Those are fields where sex differences in disease presentation and drug response are well documented but systematically underreported.
Researchers who conducted the review noted that including women in a study is not the same as studying women. A trial that recruits 40% female participants but reports only aggregate outcomes leaves the sex-specific signal buried. The policy was designed to surface that signal. A decade in, it mostly hasn’t.
The implications for prescribing practice are direct. Without sex-disaggregated data, physicians have no way of knowing whether a drug’s labeled dose, efficacy rate, or side effect risk applies to their female patients specifically. They are making clinical decisions based on evidence that was never designed to include them.
Source: Review of NIH-funded research studies, 2017-2024, examining compliance with the 2016 sex-as-a-biological-variable reporting policy. Published May 2026.
Correction: A previous version of this article incorrectly identified data reporting rules as required. The NIH policy recommended sex-disaggregated reporting. We regret the error.