It has been a little over 20 years since the National Institutes of Health (NIH) Revitalization Act of 1993 mandated, for the first time, the inclusion of women and minorities in NIH-funded clinical trials. Before then, the science that led to everything from prevention to diagnosis to treatment and even medication dosages was predicated almost entirely on male physiology, drawing on the assumption that, apart from reproductive organs, women and men were biologically the same.

It would seem impossible that throughout (and well beyond) the Women’s Rights Movement and the Civil Rights Movement there had been no movement toward promoting equity in medical research, a life and death issue for women. Even more surprising — despite the NIH Revitalization Act, equity in biomedical research is far from achieved in the 21st century.

Today, women are routinely included in clinical trials, which allows us to understand far more than we ever did about how diseases — such as cardiovascular disease and lung cancer — are expressed differently in men and women. Today, we know that “every cell has a sex” and that these differences exist down to the cellular and molecular levels — across every cell and every organ system in our bodies. Yet despite this enlightenment, and a federal law on the books, enormous gaps exist in the scientific process as it relates to the inclusion of women and the acknowledgment of sex differences.

A recent report* reveals that two decades after the landmark NIH Revitalization Act, sex-specific research is still not the norm. As a result, many women are receiving recommendations from their doctors for prevention strategies, diagnostic tests and medical treatments based on research that has not adequately included women.

The report, entitled, “Sex-Specific Medical Research: Why Women’s Health Can’t Wait,” co-authored by The Connors Center for Women’s Health and Gender Biology at Brigham and Women’s Hospital and The Jacobs Institute at George Washington University, provides evidence that the science that informs medicine either inadequately includes women or fails to consider the critical impact of sex and gender. This occurs at the early stages of research, when females are excluded from animal and human studies or the sex of the animals isn’t stated in the published results, making the entire process inequitable because sex and gender differences are often not embedded within it.

These practices exist at the same time diseases such as lung cancer, heart disease, Alzheimer’s and depression are disproportionately affecting women, raising questions about the value of current science on women’s health. The facts are startling and the lack of knowledge behind them even more so:

• Cardiovascular Disease is the number one killer of women in the United States, yet less than one-third of cardiovascular clinical trial subjects are female and less than one-third of cardiovascular clinical trials that include women report outcomes by sex.

• More women die of lung cancer each year than from breast, ovarian and uterine cancers combined; however, even when lung cancer studies include women, researchers often fail to analyze data by sex or include gender-specific factors, making it difficult to uncover differences in incidence, prevalence and survivability between men and women.

• Depression is the leading cause of disability in women worldwide. Twice as many women than men suffer from depression in the U.S., yet fewer than 45 percent of pre-clinical animal studies on anxiety and depression use female animals.

• Even though a woman’s overall lifetime risk of developing Alzheimer’s disease is almost twice that of a man, the prevailing thinking in the field is that this is simply because women live longer. However, the impact of hormonal changes at menopause and sex differences in gene expression have begun to emerge as potential explanations.

What these facts tell us is that, even in this advanced age of science, we are still leaving women’s health to chance. There are a variety of theories as to why there isn’t a more rigorous acknowledgement of sex differences in biomedical research, not the least of which is a disbelief in the problem. We have relied too heavily on the government and policymakers to carry the torch on this issue and for so many, there is the incorrect assumption that sex- and gender-equity in research is no longer an issue.