Although women make up over half the U.S. population, they have, historically been underrepresented in clinical research. As a result, clinical trials that included both men and women largely examined the average reactions in treatments across both sexes, instead of examining sex as a variable. This is problematic becuase researchers are unable to learn how women and men may react in unique ways to new drugs or therapies; indeed, there have been higher instances of women having adverse effects than men in medications and other treatments.
Due to the growing body of research that indicates diseases manifest themselves differently in men and women (meaning treatments need to be tailored to each sex), the United States Government Accountability Office (GAO) was comissioned to provide information on women's participation in NIH research. The GAO "examined (1) women's enrollment and NIH's efforts to monitor this enrollment in NIH-funded clinical research; and (2) NIH's efforts to ensure that NIH-funded clinical trials are designed and conducted to analyze potential sex differences, when applicable." Their 57 page report classifies their findings and provides recommendations moving forward. This is an important step in increasing the number of women in clinical studies as well as improving the outcomes of these studies by examining sex as a variable!