Sex Differences in Biological Research

For too long, female biology has been significantly underrepresented in basic and clinical scientific research. From animal studies that only include male subjects to clinical trials that lack women, female biology has been historically understudied. This knowledge gap has had far-reaching implications, leading to a lack of tailored healthcare solutions and an incomplete understanding of female biology.

But, thankfully, times are changing.

A new era of sex-based biology research is emerging, shedding light on the unique needs and complexities of women’s health. This research has the potential to revolutionize healthcare, leading to safer and more effective treatments and preventive measures for everyone.

Sex vs Gender

It must be noted that in this digest and in the realm of scientific research, sex and gender are distinctly different subjects. Gender refers to characteristics that are socially constructed. Sex-based biology focuses on the sex assigned at birth, which has distinct implications, spanning hormonal profiles, drug metabolism, cardiovascular events, lifespan, and even immune system responses to COVID-19.

A Bit of Policy History

Due to the historic omission of female subjects in biological research, the FDA released guidance on the Study and Evaluation of Gender Differences in the Clinical Evaluation of Drugs in 1993. This guidance recommended that drug discovery programs include pharmacokinetic screening as a tool to detect differences and analysis of safety and efficacy by sex. The NIH followed suit with their 2001 mandate created “to ensure the inclusion of women and members of racial and ethnic minority groups in all NIH-funded clinical research in a manner that is appropriate to the scientific question under study.” Further, in 2016, the NIH released their policy known as Sex as a Biological Variable (SABV), which requires researchers to include “sex” as a variable in their studies. Each of these policies has paved the way for more inclusive research.

Sex-Based Biological Research

Studying sex differences in biology includes studying an important hormone: estrogen. Estrogen, a hormone traditionally associated with the female reproductive system, is now being recognized for its broader influence on both males and females. Through rigorous investigation, estrogen is now believed to have protective effects in conditions such as hypertension, osteoporosis, and Alzheimer’s Dementia. Tulane researchers Heddwen Brooks, PhD, Jill Daniel, PhD, and Franck Mauvais-Jarvis, MD, PhD—who are key members of Tulane’s Center of Excellence in Sex-Based Biology—are working to understand the mechanisms behind the protective effects estrogen has on metabolic homeostasis, cardiometabolic health, inflammation, hypertension, and other diseases/conditions. One prominent example of the importance of studying estrogen effects is seen in post-menopausal women, who suffer from high blood pressure, asthma, and cardiovascular events at much higher rates than menopausal and pre-menopausal women. This difference is likely due to the drop in estrogen that occurs after menopause, and insights from these studies could lead to better therapeutic targets and better hospital care for both women and men, as estrogen is not exclusive to women.

Another area of interest in sex-based research is clinical pharmacology, as various studies have shown that men and women metabolize compounds differently. In fact, women are 50-75% more likely than men to experience an adverse drug reaction, likely due to differences in drug bioavailability and pharmacokinetics. In her study, Sex Differences in Pharmacokinetics and Pharmacodynamics, Offie Soldin, PhD, MBA, discussed how and why women and men have different responses to drugs. Soldin’s research was part of another university center studying sex differences—Georgetown University’s Center for the Study of Sex Differences in Health, Aging & Disease. The establishment of these types of research centers is an example of the paradigm shift currently happening, where research on biological sex differences is gaining the focus and attention it deserves.

Charting the Future of Sex-Based Biology Research

The remarkable biological differences that exist between men and women are just beginning to be understood, and researchers currently have a much better understanding of the importance of sex-based biological studies. Although we have a long way to go, we find ourselves at the dawn of a new era—a time when female representation in biological research is increasing and the knowledge gap between men’s and women’s health can begin to close. With an increased understanding of sex differences in biological research comes increased healthcare options for both men and women. Further, since mothers make approximately 80% of healthcare decisions for their children, it makes both scientific and economic sense to use the research on sex differences to promote and prioritize women’s health equity to ensure the entire population has access to safe and effective treatments.


BIO 2023

The Tulane Medicine team, who is also the Tulane Digest Team, is partnering at BIO 2023 this week. You can send a request through the BIO partnering system, or email us directly to arrange a time to connect.


Curated Research and Research-Related News Summaries, Analysis, and Synthesis. Published on behalf of The Tulane University School of Medicine. Content is generated by reviewing scientific papers and preprints, reputable media articles, and scientific news outlets. We aim to communicate the most current and relevant scientific, clinical, and public health information to the Tulane community – which, in keeping with Tulane’s motto, “Not for Oneself but for One’s Own”, is shared with the entire world.
Kaylynn J. Genemaras, PhD: Editor-in-Chief
Maryl Wright Ponds, MS: Research and Writing Assistance

Special thanks to James Zanewicz, JD, LLM, RTTP, and Elaine Hamm, PhD, for copyediting assistance

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