Understanding Why Sex is a Vital Variable for Women’s Health

Janine Austin Clayton, NIH Associate Director for Research on Women’s Health

Today, I attended the “Rock Stars of Research: Scientists Who are Shaping the Future of Women’s Health Care,” sponsored by the Endocrine Society at the Senate Visitors Center. The Endocrine Society and Northwestern University brought together leaders from the National Institutes of Health (NIH) Office of Research on Women’s Health and some of the country’s leading researchers to celebrate Women’s Health Research Day and to discuss the next big discoveries in women’s health. 

Janine Austin Clayton, NIH Associate Director for Research on Women’s Health, gave an overview of the work NIH is doing and explained the importance of having sex as a variable in all health research. According to NIH reports, “between years 1997 and 2000, the US Food and Drug Administration suspended ten prescription drugs producing severe adverse effects on the market.”

I was shocked to learn that the majority of medical research is done either solely with men, male animals, or male cells and that in other instances sex is not identified at all. It’s a basic premise of scientific research to aggregate data taking into consideration any variables that might impact your findings. Knowing all the various psychological differences between males and females, I was dumbfounded to learn that this was a norm.

How could scientist not be including women in their medical research and how could they not be measuring to see if males and females had the same outcomes? Is this another instance of the devaluation of women? I think so. What other explanation could there be for such a blatant miscarriage than women simply being viewed as insignificant?

Schematic drawing shows male-biased preclinical and clinical research can leave detrimental side effects for women undetected till marketing. ~NIH

I know that sex and gender are commonly intertwined concepts but, when it comes to science, they are very different things and have very different impacts on research. Gender is a social construct and, like many social factors, can impact behaviorally based outcomes, such as drug treatment adherence.

However sex is a scientific term that deals with the body itself. In scientific terms, when we say sex, we are talking about how people are classified based on their reproductive organs, sex hormones, gene expression, anatomy, and physiology. These things directly impact how drugs and medical treatments impact the body. The fact that sex isn’t being included as a variable in medical research is why, according to NIH, “eight of the ten drugs caused greater health risks in women.”

The 4 Cs of Studying Sex to Strengthen Science

Heart Medications in Women

  • Heart-related drugs can also affect women differently than men. While low-dose aspirin has long been given to help reduce the risk of heart attack, this recommendation has been removed for women. This is due to the greater potential for bleeding in women.
  • The drug warfarin, a blood thinner used to prevent strokes and blood clots, is one example where smaller doses are recommended for women than men. A recent article in the American Family Physician noted that a woman needs 2.5 to 4.5 mg less warfarin a week than a man.

Pain Medication and Sleep Aides

  • A large study from 2002 found that women taking acetaminophen (Tylenol) and non-steroidal anti-inflammatory medications, like ibuprofen, were more likely to have high blood pressure than those who didn’t take the drugs.
  • Women reported having more problems than men did driving the day after taking medications like Ambien the previous evening. In fact, in 2013, the Food and Drug Administration (FDA) recommended women should take only half as much Ambien as men.

NIH is making great strides to overcome this male bias in research but it’s up to you as a citizen and a consumer to stay informed and active on this issue. I urge everyone to contact their local representatives and let them know that you support NIH’s Policy on Sex as a Biological Variable. It states that, “NIH expects that sex as a biological variable will be factored into research designs, analyses, and reporting in vertebrate animal and human studies.” 


If you are a woman, ask your doctors about any medicines you are prescribed. Find out if they have been tested on women. If so, ask are there any differences in dosage, side-effects, or drug efficacy between women and men.

Letting politicians and the medical community know that we are paying attention is a great way to get them to take this issue more seriously. Learn more about NIH’s policy for the Inclusion of Women and Minorities and the work they are doing to further personalized medicine in the 21st century.

Similar Posts