‘Reproductive Resilience Hypothesis’ Highlights the Ovary as a Discovery Source in Longevity Research

By Deborah Borfitz 

Scientists at the Buck Institute for Research on Aging have used inductive reasoning to come up with a “Reproductive Resilience Hypothesis” suggesting that the ovary serves as the central biological hub helping to coordinate overall health. The proposal has implications for women before and after menopause, as well as men, who stand to benefit from what might be learned about the mechanisms controlling beneficial ovarian communication, according to Pankaj Kapahi, Ph.D., professor and researcher at the world’s first independent biomedical research institute focused solely on aging. 

There is well-established evidence backing the hypothesis and the idea that the sexes have distinct aging trajectories, he says, noting that ovarian signals are known to influence the brain, bone, metabolism, cardiovascular system, and immunity. The novelty here is in compiling these observations into a broader framework highlighting the influence of declining ovarian function on several aging processes simultaneously, as was covered in a perspective that published today in Cell (DOI: 10.1016/j.cell.2026.07.013). 

The major biological transitions that women pass through “have no direct equivalent in men,” points out Kapahi. “Pregnancy, lactation, and menopause each produce distinct and sometimes long-lasting changes … [that] do not all affect aging in the same direction. Pregnancy may impose physiological costs, lactation may provide protection against some later-life diseases, and menopause is associated with an increased risk of several chronic conditions.” 

While women generally live longer than men, they “often spend more of later life with chronic disease, frailty, or disability,” he continues. “Across animals, the pattern varies with reproductive strategy.” Where prolonged survival and caregiving improve reproductive success, females live longer, and the life-lengthening advantage is at least as good for males in species where they provide substantial parental care.  

“We’re not arguing that female longevity is universal, but that aging trajectories are shaped partly by sex-specific reproductive and life-history experiences,” says Kapahi. “What remains unclear is which signals and biological pathways drive these changes, how long their effects persist, and why the same reproductive event may be beneficial in one tissue but costly in another.” 

This also helps explain why female aging cannot be understood “simply by applying a male aging model and adding hormones,” he adds. “We need to move beyond studying only males and virgin female animals. Reproductive states should be treated as biologically meaningful, not as unwanted variability.” 

Withstanding Stress 

One of the tenets of the Reproductive Resilience Hypothesis is that evolution favors biology that strengthens the body’s ability to withstand stress, including that induced by the enormous physiological changes accompanying pregnancy. “When successful reproduction requires surviving pregnancy, lactation and years of caregiving, evolution may favor biological programs that help females tolerate, recover from, and adapt to those demands,” says Kapahi. 

Data also suggests “earlier pregnancy accelerates aging in women and increases the risk of several diseases,” he continues. “We hypothesize that reproductive resilience is beneficial and many activities like lactation and childbearing can have beneficial effects on women’s health.”  

Many factors—”number of pregnancies, their timing and spacing, maternal age, health status and whether pregnancy is followed by lactation”—may determine whether the long-term effects are protective, neutral, or harmful for individual women, Kapahi points out. “The stress is real, but so is the need for resilience, and reproductive history may shape how that balance affects later-life health.” 

One prediction of the hypothesis is that “over evolution, the ovary became deeply integrated into an inter-organ communication network linking the hypothalamus, pituitary, metabolism, immune system, bone, brain, and other tissues,” he says. “Because female reproductive success often depends on prolonged survival, pregnancy, lactation, and caregiving, ovarian signals may have become essential for coordinating reproductive state with whole-body maintenance.” 

Comparative evidence offers some support for the idea that men could perhaps extend their lifespan by helping more with childrearing. “In primates where males contribute substantially to infant care, such as owl monkeys and titi monkeys, males can have lifespan advantages over females.” Kapahi says. “That does not mean a human father automatically gains extra years by changing diapers, unfortunately. But it does support the broader idea that caregiving, and the evolutionary value of remaining healthy and alive, can shape longevity.” 

Childbearing can have neuro-endocrine effects that might activate circuits beneficial in the long run to both men and women, he speculates. The idea is backed by a growing body of evidence.  

Menopause ‘Inflection Point’ 

As proposed by the Reproductive Resilience Hypothesis, body-wide trouble begins as ovarian resilience declines. “Menopause is a normal biological transition, not a disease, but normal does not mean physiologically neutral,” says Kapahi. “The loss of ovarian communication may create a systems-level inflection point affecting bone, metabolism, immunity and the brain.” 

This is suggested by studies in mice that have had their ovaries surgically removed, he notes. Ovarian transplantation and related restoration experiments have also been shown to improve metabolic, cognitive, and other health-related outcomes in preclinical models.  

Just how much ovarian aging contributes to whole-body aging is anyone’s guess, but it is “unlikely to be the sole driver” given the importance of genetics, chronological age, lifestyle, and tissue-autonomous aging, says Kapahi. It probably also differs depending on the organ and individual. 

All this points to the beneficial effects of hormone replacement therapy, he says, although much work remains to be done to ensure it is done safely. This is a matter best decided between a woman and her physician.    

Generating Experiments 

The next step for Kapahi and his team is to “map how different reproductive states reshape organs and cell types throughout the body,” he reports. “We then need to identify the ovary-derived signals involved, including peptides, metabolites, extracellular vesicles, stromal factors, and immune mediators. We also need to understand how pregnancy changes the physiology [such] that it accelerates aging.” 

Most critically, researchers will test which signals are “necessary and sufficient for benefits in distant tissues,” says Kapahi. “Ultimately, the goal is not necessarily to extend fertility. It is to determine whether beneficial ovarian communication can be preserved or safely restored to support health later in life,” potentially benefitting both women and men. The quest involves identifying the “conserved downstream pathways controlling metabolism, immunity, stress resistance, or tissue repair.” 

Publication of the Reproductive Resilience Hypothesis comes with 11 key recommendations for improving aging research. Among those that stand out for Kapahi is making reproductive history a standard variable in aging research and medical datasets. “Information such as pregnancy, lactation, menopause, ovarian surgery, and hormone therapy may explain health trajectories that are currently being missed,” he says. 

Secondly, preclinical aging research needs to “stop treating all females as one experimental category,” continues Kapahi. “A virgin young female, a previously pregnant female, a lactating female, and a post-reproductive female are biologically different states” and only using virgin females may conceal important effects of those distinct states. 

Kapahi additionally stresses the need to “identify the signals through which the ovary communicates with the rest of the body and determine whether beneficial signals can be restored without extending fertility. That could provide the greatest translational payoff because it may reveal upstream ways of protecting several organs together rather than treating each disease separately.” 

The big take-home message is that “female biology should not be treated as a complicated variation of a male default,” he adds. “Reproductive history is a fundamental part of how women age, and the ovary may influence health far beyond fertility.” Ovarian rejuvenation research is thus expected to help slow age-related diseases.  

The Reproductive Resilience Hypothesis is designed to generate experiments rather than make clinical recommendations, Kapahi emphasizes. “Studying the mechanisms that allow females to withstand reproduction, caregiving, and physiological stress could reveal new ways to extend healthy life for everyone.” 

Historically, female reproductive biology has been viewed as an “added complexity rather than a source of discovery,” he says, so their changing biological states were often treated as “variables to control rather than biological transitions that could teach us something fundamental about aging. We propose that the investment in reproduction and care of children that females make is the reason for their extended longevity, in terms of evolution, and has a lot to teach us about aging and how to deal with age-related diseases.”