For many years, scientific research was conducted using models that were primarily male. Scientists gradually started to notice the bias toward male subjects in the nineties, and the National Institutes of Health started to require that in human studies, females had to be represented. It’s only been a fairly recent event that steps have been taken by the National Institutes of Health to ensure that both sexes are adequately represented in research studies.
As time went on it became evident that results that had been obtained using male models were not always applicable to females of the species. Hypersensitivity to pain works differently in males and females, for example. In the last decade, several drugs have been taken off the market because they affected women more than men. In the video, you can see how one neuroscientist came to appreciate gender differences because of what happened with Ambien. Looking at how those drugs were developed, it shows that male cells and animals had been used to create them.
An endocrinologist at Tulane University is working on solving this problem. "We really need to study both sexes," says Dr. Franck Mauvais-Jarvis, who is one of the drivers of the effort to balance the gender disparity in research. "The focus on a single sex threatens to limit the impact of research findings as results may be relevant to only half of the population.”
Although the NIH did start to require scientists to respond to sex differences in their work, they did not outline how to go about doing that. Mauvais-Jarvis has published a report in Cell Metabolism which aims to guide scientists that are working to understand metabolic disorders such as obesity and diabetes to properly account for the differences in the sexes in their research. The publication discusses the reasons why sex differences arise in research, and how investigators can take that into account when utilizing research models and designing studies that will account for those differences.
Mauvais-Jarvis wants researchers to know that sex differences are not simply some superficial aspect of research that can be disregarded because it’s as simple as an alternative set of hormones. He has suggested that females and males have two different biological systems.
"Sex differences are at the core of the mechanism for biological traits and disease," Mauvais-Jarvis noted. "We believe that the incorporation of appropriately designed studies on sex differences in metabolism and other fields will accelerate discovery and enhance our ability to treat disease. This is the fundamental basis of precision medicine.”
In the video, you can hear Dr. Rajita Sinha, a Professor of Neurobiology and Child Study in the Department of Psychiatry at Yale University discussing how critical it is for researchers studying addiction and substance abuse to account for gender in their research.