Biomedical Researchers' Perceptions of the NIH's Sex as a Biological Variable Policy for Animal Research: Results from a U.S. National Survey

<strong><em>Background:</em></strong> In 2015, the National Institutes of Health (NIH) established a policy on sex as a biological variable (SABV) in an effort to address the overrepresentation of men and male animals in biomedical research and the lack of attention to sex-based responses to medical treatments. However, questions remain regarding how U.S. biomedical researchers perceive the impact of the SABV policy on their own research and on translational science more broadly. <strong><em>Materials and Methods:</em></strong> A national survey of U.S. scientists who use vertebrate animals in their research was conducted. Respondents were asked how they select and use animal species as model organisms as well as how they perceive the impact of the SABV policy on their research practices. <strong><em>Results:</em></strong> Almost all respondents reported that they had previously heard of the NIH SABV policy, and over one-third had altered their study designs to comply with the policy. There were robust differences in perceptions of the SABV policy based on researchers' primary species of model organism. However, there was no significant difference in the likelihood of researchers analyzing their results by sex based on whether they had received recent NIH funding. <strong><em>Conclusions:</em></strong> While many researchers report adhering to the SABV policy requirements, more work needs to be done to ensure that the policy is being evenly applied to researchers using all types of animal models and that researchers adhere to the policy after receiving NIH funding, particularly in terms of reporting on and analyzing SABV in their study findings for publication.