Since 2016, the US National Institutes of Health (NIH) has required those it funds to consider sex as a biological variable in their experimental design, analyses and reporting of preclinical studies: in other words, they should include female animals equitably, where necessary for rigour. To explore how the policy has been working, we surveyed the scientists who review NIH grant applications — called study-section members — in September 2016 and October 2017. In their responses, we found cause for both commendation and concern.
These reviewers report that an increasing number of investigators are incorporating the policy into their submissions (for details, see N. C. Woitowich and T. K. Woodruff J. Womens Health 28, 9–16; 2019). In 2017, 68% thought that considering sex as a biological variable is important for NIH-funded research, and 58% thought that implementing the policy would improve the rigour and reproducibility of biomedical research. Although study-section members are a subset of all biomedical scientists, their views are an important proxy for the promise of this policy for improving scientific discovery and outcomes.
The quantitative data were positive overall, but female study-section members in the 2017 cohort (the minority) were significantly more likely than men to view the sex-inclusion policy as favourable.
Open-ended comments revealed variability in how policy adherence was judged to affect grant scoring. Some did not consider the policy to be a score-driving factor. Others differed on how it relates to costs and to the overuse of experimental animals. Federal and local dialogue and education should address those concerns.
The swift uptake of the sex-inclusion policy contrasts with the slow progress on the inclusion of women and minorities in NIH-funded clinical research, as stipulated in the 1993 NIH Revitalization Act (S. E. Geller et al. Acad. Med. 93, 630–635; 2018).
Nature 565, 25 (2018)