May 16, 2014

Fixing (the Other) Gender Bias in Scientific Research

by Christine Hoekenga

white lab mouse

Animal test subjects, such as mice and rats, are at the root of most health and medical research, but female animals are rarely used in testing.
Image courtesy: Giang Hồ Thị Hoàng (Flickr CC)

You’ve probably heard about research indicating that–despite significant progress–there is still a gender gap in science. Women are underrepresented in many STEM fields. They may face subtle biases from professors and potential mentors. And, on average, they are paid less than their male counterparts.

But this week, the National Institutes of Health (NIH) announced an important shift to address a different gender bias in science: the lack of female test animals used in the basic biomedical research that ultimately helps us understand health and disease.

Most drugs, medical devices, and  procedures are tested in animal models, such as mice, before any human testing is conducted. Over the past few decades, the medical research community has evened out the numbers of male and female subjects participating in human studies, but early testing in animals continues to disproportionately rely on male test subjects. In fact, many studies use only male test animals–and yet the results help inform our understanding of disease and the development of treatments for both men and women.

Why does this matter?

Increasingly we are finding that sex and gender can play a major role in how (and if) diseases affect people, how effective drugs and other treatments will be, and what side effects treatments may cause. Examples that have recently surfaced include:

  • differences in the way women and men metabolize drugs, such as the insomnia medication zolpidem, requiring  doctors to prescribe different dosages in order to be effective
  • women being more susceptible than men to multiple sclerosis, but developing less-severe forms of the disease
  • preventative measures, such as taking low-dose aspirin to reduce the risk of heart attack, having different results in men than women
  • different biological triggers and patterns in male and female substance abuse, which may point to different treatment approaches

The NIH noted a similar issue with the cells and tissues used in labs. Frequently, cell cultures used in research are derived from male organisms, giving the cells themselves male characteristics. As Janine Clayton, director of the NIH Office of Research on Women’s Health explains, “every single cell has a sex, and the sex of the cell affects the biological and biochemical properties of the cell, and that’s important in research.”  For example, female and male cells may respond differently when exposed to microbes or chemical compounds. And these differences may be magnified further if the cells are exposed to sex hormones they would normally encounter as part of a living organism.

All this means that what’s good (or bad) for a male cell or mouse may not be good (or bad) for a female cell or mouse. And those differences may prevent researchers from accurately predicting how their research will ultimately apply to women and men. So what is the NIH doing to address this?male and female gender icons

In a Nature article published Wednesday, Clayton and NIH director Francis Collins, laid out steps the agency will start taking this fall to address these gaps, including:

  • policies that require researchers applying for NIH funding to report the balance of male and female cells and animals they plan to use in their research
  • continued funding for the Specialized Centers of Research on Sex Differences program, which “supports interdisciplinary collaborations on sex and gender influences in health”
  • training for NIH grant reviewers and changes to its grant review process to ensure this balance is considered in funding decisions
  • partnerships with peer-reviewed journals to promote research that offers insight into sex differences.

“Our goal is to transform how science is done…” the authors say.  “This move is essential, potentially very powerful and need not be difficult or costly.”

Read the full Nature article and hear a podcast interview with Janine Clayton outlining the issues and how NIH plans to address them.

For more on how peer reviewers and funding program directors respond to and help shape research proposals, see our module Peer Review in Scientific Publishing.

Visit the NIH Office of Research on Women’s Health for resources about the roles that sex and gender play in health, wellness, and disease.


Christine Hoekenga

Written by

Christine is a freelance writer, editor, and content strategist, specializing in science and nature. She holds an Bachelor's degree in Environmental Science and Media Studies and a Master's of Science Writing. She has been working in science communication and education for nearly a decade as a journalist, an organizer for conservation groups, and a museum educator. Before joining the Visionlearning team, she served as the New Media and Online Community Manager for the Webby award-winning Smithsonian Ocean Portal. Christine is assisting Visionlearning with developing new modules and glossary terms, managing the blog, and outreach through social media.