- December 2000

Organization News - American Coalition for Fathers and Children
1718 M Street, N.W. Suite 187, Washington, D.C. 20036

Were women excluded from medical research?

Rhetoric and the Reality


From Men's Health America, P.O. Box 1404 Rockville, MD 20849

Executive Summary

It has often been claimed that women were routinely excluded, neglected, or otherwise shortchanged by medical research sponsored by the National Institutes of Health (NIH). This report analyzes these claims from three perspectives:
  1. The number of studies that included men and women
  2. Overall sex-specific enrollment figures
  3. Budget allocations for sex-specific research

This report is based on a variety of sources, including published research, statistics from the NIH Office of Research on Women's Health, the recent report on gender health research issued by the U.S. General Accounting Office, the Medline database, and other sources.

This analysis consistently points to three conclusions:

  1. Historically, women participated in 95% of NIH clinical trials. Thus, women were routinely included in NIH research.

  2. Men have historically been underrepresented in research on cancer, reproductive health, and sex hormones.

  3. In the past, gender representation in medical research was approximately equal. Now, men represent only 37% of participants in NIH funded research, and gender-specific budgets favor women by more than a 2:1 margin.

The allegation that women were generally shortchanged by NIH research is not supported by the facts. The claim also obscures the current shortfall in men's health research.


It has often been argued that women were shortchanged by medical research conducted at the National Institutes of Health (NIH). The following statements summarize this point of view:
  • "Medical research has been mainly done on men, for the benefit of men only." -- National Women's Health Network, 1994

  • "When it comes to health care research and delivery, women can no longer be treated as second-class citizens." -- President Bill Clinton, quoted in the Washington Post, October 19, 1993, p. A1.

  • "Blatant discrimination!" -- Sen. Barbara Mikulski's reaction when she learned that only 9.7% of the 1990 NIH research budget was devoted specifically to women's health.

  • The NIH Office of Research on Women's Health was established "in response to a report by the U.S. General Accounting Office . . . that women were routinely excluded from medical research supported by NIH." -- Vivian Pinn, NIH News and Features, Fall 1997, p. 3

  • "Historically, research studies were conducted only with men." -- National Institute of Mental Health: Women Hold Up Half the Sky, 1999

  • The Women's Health Initiative was necessary to "address many of the inequities in women's health research." - WHI Backgrounder

  • The participants in the Framingham Heart Study were "all male." -- Ruth Kirschstein, NIH Acting Director, January 28, 2000

These types of statements have been repeated so many times that the American public now accepts them as true. As a result, there is a widespread belief that medical research should compensate women for past neglect, which justifies the current imbalance in gender-specific research for women. In addition, medical screening and treatment programs that exclude men have been launched around the country, again with the justification that past neglect needs to be remedied.

But is it true that women were routinely excluded or generally shortchanged? This report summarizes an extensive review of three indicators of sex-specific participation in medical research:

  1. Numbers of clinical trials that included men and women;
  2. Gender-specific enrollment figures;
  3. Sex-specific budget allocations

Our focus is on medical research sponsored by the National Institutes of Health, the nation's premier federal research agency. We do not address medical research conducted by the Food and Drug Administration, by the Department of Defense, or in the private sector.

Part I of this report examines gender-specific research at the NIH as a whole. Part II looks at disease-specific research. Part III identifies areas in which men have been underrepresented. The final conclusions are presented in Part IV.

I. Gender-Specific Research at the NIH as a Whole

Over the past 30 years, men have died 6-7 years sooner than women. And for each of the top 10 causes of death, men have had a higher mortality rate (1). Scientists generally devote more attention to groups that are at higher risk for death. So how is this reflected in the sex-specific research patterns at the entire National Institutes of Health?

A. The 1979 NIH Inventory of Clinical Trials lists 293 studies. A review of the 293 studies revealed that 268 trials included both men and women, representing 91% of the total (2). Of the remaining 25 studies, 12 were male-only and 13 were female-only. Thus, women were included in 96% of clinical trials. A second analysis that examined NIH trials during the same period reached a similar conclusion (3).

B. In 1994, the U.S. Congress passed the NIH Revitalization Act (PL 103-43). The law called for equal gender participation, and mandated the establishment of a computerized tracking system of enrollees in NIH research.

Everyone expected the system to reveal widespread bias in favor of men. In 1994, 44.9% of the enrollees in extramural research were found to be male and 51.8% were female, while the sex of the remaining enrollees was unknown (6). By 1997, males represented only 37.1% of all participants in extramural research, compared to 61.9% females (5). It is unlikely that 37% male participation is consistent with the intent of the NIH Revitalization Act.

C. In 1979, single-sex studies were evenly divided between men and women, representing a 1:1 ratio (2). In 1994, the NIH funded 90 men-only extramural studies, compared to 203 women-only studies, creating a 1:2 disparity (7). The number of single-sex studies expanded considerably in the next three years, and by 1997, the NIH funded 244 male-only studies, compared to 740 female-only studies (3), a 1:3 disparity.

Persons have been led to believe that these female-only studies examine female reproductive health and other conditions that occur primarily in women (7). A review of the actual studies, however, paints a very different picture. A listing of the 1997 studies reveals hundreds of female-only studies on conditions that commonly affect men. These studies include the following:

AIDS, aging, Alzheimer's disease, arthritis, cancer prevention, chronic lung disease, cognitive functioning, community outreach to underserved populations, contraceptives, coronary artery disease, depression, domestic violence, drug-dependency, family development, functional bowel disorders, genetics and chromosomal mapping, H pylori infection, hypercholesterolemia, hypertension, insomnia, ionizing radiation, irritable bowel syndrome, leukemia, myotonic dystrophy, obesity, parenting, pediatric injuries, post-traumatic stress disorder, sex hormones, skin cancer, sleep apnea, smoking cessation, stress, vitamins/minerals and cancer risk, thyroid cancer, toxic exposures, and many others.

A letter to the editor in the Journal of the American Medical Association identifies another example of a single-sex study that inappropriately excluded males (8).

It appears that the growth in female-only protocols largely explains the declining percentage of male enrollment in NIH research. The current shortfall in male participation in NIH research is not explained by men "not showing up" for the studies-it is due to the rapid increase in the number of studies that are designed for one sex only.

D. Beginning in 1988, the NIH began to analyze research funding on a sex-specific basis. That year, men's health garnered 4.4% of the NIH research budget, compared to 9.7% for women's health (4). By 1999 the disparity had increased, with 6.4% budgeted for men's health, compared to 15.5% for women's health (5). Thus, the sex-specific funding for men's health has lagged behind women's health by at least a 1:2 margin.

What about the assertion by the NIH Office of Research on Women's Health that the U.S. General Accounting Office had concluded that "women were routinely excluded from medical research supported by NIH"? A review of the GAO report reveals no such statement. Although the report contains one anecdotal example of an all-male study, the report concludes, "there is no readily accessible source of data on the demographics of NIH study populations" (9). If no data on overall study demographics were available, how can anyone infer that any group was "routinely excluded"?

II. Disease-Specific Research

Next we look at the published research for 25 common medical conditions, and then analyze disease-specific research for heart disease and cancer.

Medline Analysis

Medline is the best-known database of published medical research. Since 1966, every article in the major medical journals has been coded for the medical condition, gender composition, type of research, and other characteristics. Medline is free, easy-to-use, and can be accessed at

We analyzed the Medline database for the time period 1966-1990, the period when women were alleged to have been frequently excluded. We identified clinical trials because these represent a more rigorous type of research than case reports. Studies performed on animals were excluded. We searched for all of the leading causes of death in the United States, as well as for other conditions commonly researched at the NIH. We have included information only on conditions for which five or more clinical trials were reported during that time period. Leading causes of death are indicated with an asterisk.

This table shows there were 753 studies that included men, compared to 854 studies that recruited women. Inspection of the individual studies reveals that most included both men and women-these studies are included in the counts of each of the two columns. This is consistent with previous reports that reveal the routine inclusion of women in NIH research (2, 3).

Number of Clinical Trials on Humans Published in the United States
1966-1990, by Topic and Gender:
Condition No. W/ Men No. W/ Women
AIDS* 20 12
Arthritis 19 22
Atherosclerosis 13 6
Asthma 11 11
Cancer* 141 194
Cancer - Breast 8 71
Cancer - Prostate 22 -
Contraception 2 10
COPD* 16 15
Depression 25 23
Diabetes* 25 20
Heart Attack 59 37
Heart Disease 137 78
Heart Failure 7 6
Hypertension 91 69
Flu* 7 4
Injuries* 18 22
Manic-depressive Dis. 6 6
Mental health 29 27
Reproduction 20 139
Schizophrenia 11 6
Sex Hormones 2 (Testosterone) 25 (Estrogen)
Sexually Transmitted Dis. 37 28
Stroke* 22 19
Suicide* 5 4
TOTAL 753 854

Heart Disease

Men have long faced twice the risk of heart disease mortality, compared to women. For example, men's risk of dying from heart disease in 1980 was 280.4/100,000, while women's risk was only 140.3/100,000 (1). And men are likely to develop heart disease at a younger age than women, which makes the social and economic impact of heart disease of greater importance among men.

A. The NIH Acting Director made the statement at a public health conference on January 28, 2000 that the participants in the landmark Framingham Heart Study were "all male." But according to a report by the NIH National Heart, Lung, and Blood Institute, 45% of the participants in the early Framingham Heart Study were male and 55% were female (10).

B. An analysis of four major hypertension studies conducted in the 1970s and 1980s-Hypertension Detection and Follow-up Program, Mayo Clinic Three-Community Hypertension Control Program, Treatment of Mild Hypertension Study, and Pitt County Study-found that women made up nearly half of the study participants (11).

C. An analysis of 191 trials on myocardial infarction published 1960-1991 found that women composed 20% of study participants (12). Much of this difference can be explained by the fact that the studies placed more emphasis on recruiting younger patients with less co-morbidity--predominantly males. And only 23.8% of these studies were conducted in the United States, so it is not possible to tell to what extent the NIH-funded studies account for the 20% figure.

D. A review of clinical trials published 1966-1990 (taken from the table in the previous section) reveals the following counts. Most of these studies included both men and women, and are included in both columns:

Condition No. W/ Men No. W/ Women
Atherosclerosis 13 6
Heart Attack 59 37
Heart Disease 137 78
Heart Failure 7 6
Hypertension 91 69
TOTAL 307 196

Men's risk of dying from heart disease exceeds women's risk by a 2:1 margin. And the number of heart studies that include men exceeds the numbers of clinical trials with women by a 3:2 margin. Thus, when men's greater risk of death is taken into account, it is unlikely that women were underrepresented in heart disease research. As the prestigious Institute of Medicine put it, "The literature is inconclusive about whether women have been excluded or importantly underrepresented in clinical trials" (13).


Overall, men suffer from an approximately 50% greater risk than women of dying from cancer. And while cancer death rates in women have declined since 1950, cancer deaths in men have actually increased (1). This would suggest that greater attention should be placed on cancer in men than in women. How has the NIH focused its cancer research efforts?

A. An analysis of 1989 enrollees in National Cancer Institute (NCI) Clinical Trials Cooperative Group Program reported only 43% male participation (14). The analysis reported almost 40 clinical trials for breast cancer, compared to 10 trials for prostate cancer.

B. A report from the Southwest Oncology Group revealed that only 42% of study enrollees for the period 1993-1996 were males (15, 16). Interestingly, of the 5,122 patients in breast cancer trials, none were men, even though males represent 1% of all breast cancer cases.

C. The recent GAO report states that by 1997, the representation of men in NCI research had fallen to only 29% of participants (3).

D. Each year, the number of men diagnosed with prostate cancer is similar to that of women detected with breast cancer. But since at least 1991, prostate cancer research has lagged behind breast cancer. In 1991, $13.8 million was allocated to prostate research, and $92.7 million to breast research (17). By 1998, $89.5 million went to prostate research, compared to $348.6 million for breast research. This represents a 1:4 disparity.

Men have a greater risk of dying from cancer. But ironically, men have long been underrepresented in cancer research, whether judged on the basis of gender-specific enrollment figures or budget allocations. This disparity has worsened in recent years.

III. Areas in Which Men Have Been Underrepresented

Sections I and II examined research patterns to identify whether women were routinely excluded. But are there areas where men's health has received less attention than its due?

A. Cancer

As documented above, men have long been underrepresented in cancer research, based on a review of the following:
  • Overall number of studies;
  • Enrollment figures in cancer research studies;
  • Comparisons of budget allocations for prostate vs. breast cancer;
  • Comparisons of published studies for prostate vs. breast cancer;

B. Sex Hormones

Sex hormones have a major impact on health and quality of life for both men and women. A Medline search for the years 1966-1990 reveals that there were only two clinical trials on testosterone, compared to 25 clinical trials on estrogen. Thus, testosterone research lags by a 1:12 ratio.

C. Reproductive Health

Reproduction is an issue that affects men and women equally. And a major World Health Organization study found that a couple's inability to conceive is just as often linked to male infertility as female infertility (18). Yet a Medline search for 1966-1990 on the topic of reproductive health identified only 20 clinical trials for men, compared to 139 trials for women, a 1:7 disparity.

Thus, men have historically been underrepresented in medical research in at least three areas: cancer, sex hormones, and reproductive health.

IV. A Misrepresentation of the Great Weight of Evidence

This study points to three conclusions about sex-specific research at the National Institutes of Health:
  1. Historically, women participated in about 95% of NIH clinical trials. Thus, women were routinely included in-not excluded from- NIH research.

  2. Men have historically been underrepresented in research on cancer, reproductive health, and sex hormones.

  3. In the past, gender representation in medical research was approximately equal. Now, men represent only 37% of participants in NIH-funded research, and gender-specific budgets favor women by more than a 2:1 margin.
As cited in the Introduction of this report, claims about the status of women's health research have been made by advocacy groups, politicians, and even by officials of the National Institutes of Health. Based on the information presented in this report, we can state with certainty that women were never routinely excluded, neglected, or shortchanged by research conducted at the NIH.

A forthcoming book by Yale University researcher Sally Satel reveals other examples of claims of gender bias that eventually turned out to be one-sided or entirely false (19). Columnist Cathy Young is more pointed in her critique: "The women's health movement is based on a myth that . . . women were the victims of abuse and neglect by a male medical establishment" (20).

The allegation that women were routinely excluded by NIH research represents a spurious misrepresentation of the great weight of evidence. The claim also obscures the fact that in the past decade, men's health research has been shortchanged to an unprecedented degree.


  1. Department of Health and Human Services: Health, United States, 2000, Table 30.

  2. Meinert CL. Memo to Co-chairs of the NAS/IOM Committee on the Legal and Ethical Issues Relating to the Inclusion of Women in Clinical Studies, May 5, 1993. Cited in Mastroianni AA, Faden R, Federman D (eds.). Women and Health Research. Vol. I. Washington DC: National Academy Press, 1994, Appendix A.

  3. Dickersin & Min. NIH clinical trials and publication bias. Online J Current Clin Trials. Doc. 50. April 28, 1993.

  4. NIH Office of Research on Women's Health. NIH Support for Research on Women's and Men's Health Issues, Fiscal Years 1988, 1989, and 1990.

  5. General Accounting Office: Women's Health. GAO/HEHS-00-96, May 2000.

  6. NIH Office of Research on Women's Health. Implementation of the NIH Guidelines on the Inclusion of Women and Minorities as Subjects in Clinical Research, December 1998.

  7. Hayunga EG, Costello MD, Pinn VW. Demographics of study populations. Applied Clinical Trials 1997; 6: 41-45.

  8. Bartlett EE. Long-term neuroendocrine effects of childhood maltreatment. JAMA 2000 (in press).

  9. Nadel MV. National Institutes of Health: Problems in implementing policy on women in study populations. Washington, DC: U.S. General Accounting Office GAO/T-HRD-90-38. June 18, 1990.

  10. National Heart, Lung, and Blood Institute Advisory Council: Women's Health Issues. Presented at the 159th Meeting. National Institutes of Health: Bethesda, MD, Sept. 6, 1990.

  11. Young C, Satel S. The Myth of Gender Bias in Medicine. Washington, DC: Women's Freedom Network, 1997, p. 6.

  12. Gurwitz JH, Col NF, Avorn J. The exclusion of the elderly and women from clinical trials in acute myocardial infarction. JAMA 1992; 268: 1417-1422.

  13. Bennett JC: Inclusion of women in clinical trials. New Engl J Med 1993; 329: 288-291.

  14. Ungerleider RS, Friedman MA: Sex, trials, and datatapes. J National Cancer Institute 1991; 83: 16-17.

  15. Hutchins LF, Unger JM, Crowley JJ et al: Underrepresentation of patients 65 years of age or older in cancer-treatment trials. New Engl J Med 1999; 341: 2061-2067. Table 1.

  16. Bartlett EE. Patients 65 years of age or older in cancer-treatment trials. New Engl J Med 2000; 342: 1531.

  17. National Cancer Institute: Research Dollars by Various Cancers.

  18. World Health Organization. Towards more objectivity in diagnosis and management of male infertility. Results of a WHO multicenter study. Int. J Androl 1987; Suppl. 7.

  19. Satel S: PC, M.D.: How Political Correctness is Corrupting Medicine. New York: Basic Books, 2001.

  20. Young C. Keep gender politics out of medicine. Detroit News, September 21, 2000.

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