The Society for Women's Health Research has long advocated that research studies on diseases that impact men and women should consider sex as a fundamental variable. Thankfully, this attitude seems to be evolving. Recently, the National Institutes of Health (NIH) reported that it will issue new policies on the inclusion of female animals and cells in preclinical medical research. We look forward to working with the NIH and the Office of Research on Women's Health as they develop new policies that require grant applicants to report their plans for including a balance of male and female animals and cells in preclinical studies as appropriate.