An example of the intersection of sexism, speciesism and ableism in scientific research.
Female animals have typically been excluded from research on the basis that fluctuating hormones would render the results uninterpretable. The stereotype of the ‘rational and orderly male mind’ versus a ‘complicated and hormonal female mind’ has skewed research towards using almost exclusively male mice, rats or other animals in experimentation.
“People like to think they’re being objective and uninfluenced by stereotypes but there are some unconscious biases that have been applied to how we think about using female animals as research subjects that should be looked at by scientists” says Rebecca Shanky, a neuroscientist at Northeastern University (Boston).
More and more researchers are advocating for the inclusion of female animals in research. Scientific evidence shows that the hormones and behaviour of male rodents are sometimes even less stable than those of females.
“The belief that non-human female mammals are intrinsically more variable than males and too troublesome for routine inclusion in research protocols is without foundation” (Beery & Zucker 2011).
Researchers say that male animal bias is unjustified and can for example lead to drugs that work less well for women.

EDIT 2019/07/18: This article is not a plea to include more animals (female animals) in experimentation. It is a constatation. This exclusion is also embedded in human experimentation (male bodies as the standard).
Knowing the system is a prerequisite for challenging and dismantling the system.
LINKS
Beery A.K & Zucker I, Sex Bias in Neuroscience and Biomedical Research, Neurosci Biobehav Rev., 2011 Jan; 35(3): 565–572.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3008499/
“The NIH mandated enrollment of women in human clinical trials in 1993, but no similar initiatives exist to foster research on female animals.”
“The belief that non-human female mammals are intrinsically more variable than males and too troublesome for routine inclusion in research protocols is without foundation.”
Shansky R.M., Are hormones a “female problem” for animal research?, Science, 31 May 2019:
Vol. 364, Issue 6443, pp. 825-826.
https://science.sciencemag.org/content/364/6443/825
“One of the most deep-seated misconceptions about the human psyche is that men are simple and women are complicated”
Prendergast B.J., Onishi K.G., Zucker I., Female mice liberated for inclusion in neuroscience and biomedical research, Neurosci Biobehav Rev. 2014 Mar;40:1-5. https://www.ncbi.nlm.nih.gov/pubmed/24456941
“The underrepresentation of female mice in neuroscience and biomedical research is based on the assumption that females are intrinsically more variable than males and must be tested at each of four stages of the estrous cycle to generate reliable data.”
Interesting. Honestly, I had no idea that male mice are used WAY more than female mice for testing. I learned something new!
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