Why Overlooking Female Biology Still Impairs Drug Development

By Bio-IT World Staff 

November 12, 2025 | Though gender equity efforts in research have made strides, progress has plateaued. Roughly two-thirds of pivotal clinical trials leading to the U.S. Food and Drug Administration (FDA) drug approvals now include women at rates proportional to their disease burden, but the problem is “fundamental issues in not considering female biology,” according to Sophie Zaaijer, Ph.D., clinical and translational scientist at the University California Irvine and Riverside. 

“We are stuck in treating women as if they are mini men,” she continues. Zaaijer argues that bridging the gap between inclusion and understanding will require considering the “alternate disease states” of women. Whether it’s molecular pathways or clinical applications, women are biologically different than men and should be looked at separately. Diversity in trial enrollment means little if the biological data pipeline remains male-dominated. 

In preclinical drug discovery, the sex and ancestry of cell models are rarely considered, a bias that can occur through every stage of research. Current diagnostics also only capture snapshots of disease rather than disease trajectories. Women’s hormonal fluctuations are also not considered, even though they influence inflammation, metabolism, and immune responses, creating complex temporal patterns that traditional diagnostics overlook. 

According to Michael Liebman, Ph.D., managing director at digital healthcare modeling and analytics company IPQ Analytics, nearly 90% of drug failures stem from how a disease is defined in terms of both diagnosis and the disease state of the people being tested, which “is much better understood for men compared to women.”  

 “We are searching for our keys under a lamppost ... but not beyond that beam and therefore we miss a lot,” he continues. Liebman’s work with artificial intelligence showcases that drug development is affected by outdated, static diagnostics with male-dominated outputs.  

At Bayer AG, Kirsten Leineweber, Ph.D., is mapping genomic variants that shape individual risk and resilience to disease—an approach that could redefine precision medicine by linking female-specific genetic mosaics to phenotypic outcomes. Meanwhile, companies like Generational Science & Discovery, led by CEO and founder Katie Baca-Motes, are deploying wearables and eDiaries to capture longitudinal hormonal data—including perimenopause and menopause, as well as monthly fluctuations—that can contextualize treatment responses in real time. 

The field’s next frontier, says Zaaijer, is to move from inclusion to integration. Trials need to start measuring, rather than ignoring, the biological rhythms of women’s health. With the FDA’s 2019 enrichment guidance allowing studies to incorporate time-specific measurements such as hormonal cycles, companies now have both the tools and regulatory support to transform female-aware trial design from concepts and aspirations to standard practice. 

To read the full story written by Deborah Borfitz, head over to Clinical Research News.