Science
A structure attached to the ovary was written off as useless for over a century. In 2025, scientists showed it may be doing real work. That story is the whole women's health research gap in miniature.
Comedian Michelle Wolf recently went viral for being angry about the rete ovarii, a tubular structure connected to the ovary that quietly vanished from modern anatomy textbooks. Her line: we study women's health "about as thoroughly as a man looks for ketchup in the fridge."
The forgotten structure next to your ovary
The rete ovarii is a network of tiny tubes attached to the ovary. For 150 years it was treated as leftover developmental scrap. New research suggests it may help the ovary function.
Dismissed, then deleted
The rete ovarii was first described in 1870. With no obvious purpose, scientists labeled it a vestige and mostly ignored it for over a century. It appeared in early editions of Gray's Anatomy, then dropped out of modern textbooks.
To be fair, it was never erased from science entirely. A 1999 paper looked at hormone receptors in the human rete ovarii. But it was never treated as worth a serious look.
Rediscovered by accident
Developmental biologist Jennifer McKey, then at Duke University, was imaging whole mouse ovaries when she noticed a horseshoe-shaped structure curving around the organ. She dug through old literature and matched it to the long-forgotten rete ovarii.
What the 2025 study found
In March 2025, Dilara Anbarci and colleagues published "Rediscovering the rete ovarii, a secreting auxiliary structure to the ovary" in eLife. Working in mice, they found:
Three distinct regions that persist into adulthood: the intraovarian rete, the connecting rete, and the extraovarian rete.
Active fluid flow toward the ovary. Using a dye too large to seep through tissue passively, the team tracked fluid moving through the rete into the ovary.
Secreted proteins in the fluid that may matter for ovarian function.
Blood vessels, immune cells and nerve fibers surrounding the outer region, consistent with a sensory role.
An earlier dataset from the same group found genes in the rete switching on when estrogen peaked, including one tied to egg maturation and follicle maintenance. Anbarci compares the structure to an antenna that tunes in to hormonal signals.
What we still don't know
This is early science, and we want to be honest about that. The work is in mice. Nobody has yet shown that fertility or hormone health changes when the rete is removed, or that it works the same way in humans. An accompanying eLife commentary notes its role in adult ovaries remains unclear.
That uncertainty is exactly the point. A structure physically connected to one of the body's main hormone-producing organs went unstudied for 150 years. The question is how many other answers about women's bodies are sitting in that same blind spot.
How women got left out of the lab
For 16 years, US drug guidance kept most women of childbearing age out of early clinical trials. Even lab mice were mostly male. We are still living with the data gap that created.
The default human was a man
After the thalidomide birth-defect tragedy, the FDA issued a 1977 guideline that barred most women of "childbearing potential" from early-phase drug studies. The intent was protecting pregnancies. The effect was a generation of medicines tested mainly on men, then prescribed to everyone.
The usual justification was that hormone cycles make women "messy" research subjects. Researchers at UC Berkeley and the University of Chicago call that concern unfounded. Female variability isn't noise to be avoided. It's biology to be studied.
The key turning points
Year | What changed |
1977 | FDA guideline excludes most women of childbearing potential from Phase I and early Phase II trials (source) |
1986 | NIH encourages researchers to include women in studies (source) |
1993 | NIH Revitalization Act makes inclusion of women in NIH-funded clinical research federal law; FDA formally lifts the 1977 restriction (source) |
2016 | NIH requires grant applicants to account for sex as a biological variable in animal and human studies, or justify single-sex designs (source) |
The mice were men too
The bias ran all the way down to the petri dish. When a Northwestern University team reviewed published research, 80% of animal studies and 71% of cell studies used only male data. One neuroscientist admitted he had used only male mice for years simply because it was cheaper.
NIH's 2016 "sex as a biological variable" policy was meant to fix this. Its future is now uncertain, after much of the supporting guidance was removed from the NIH women's health office website in 2025.
Inclusion isn't the same as analysis
Women now enroll in trials in large numbers. But many studies still fail to analyze results by sex. Putting women in a study and then averaging them together with men still hides the differences that matter.
Part 3: The price of one-size-fits-men medicine
When women aren't studied, they get doses calibrated for men, diagnoses calibrated for men, and years of waiting. The evidence is not subtle.
Twice the side effects
A 2020 analysis by Irving Zucker and Brian Prendergast in Biology of Sex Differences reviewed 86 FDA-approved drugs. Given the same dose as men, women usually had higher drug levels in their blood and cleared them more slowly. Women experience adverse drug reactions nearly twice as often as men, and the authors conclude that equal dosing risks routinely overmedicating women.
The sleeping pill dose that took two decades to fix
Zolpidem (sold as Ambien) reached the US market in the early 1990s. Only in 2013, the FDA cut the recommended dose for women in half, from 10 mg to 5 mg, because women clear the drug more slowly and faced a higher risk of next-morning impairment, including while driving.
Misread hearts
A University of Leeds study of nearly 600,000 heart attack patients in England and Wales found women were 50% more likely to receive the wrong initial diagnosis. One reason: the standard troponin blood test used thresholds that miss heart attacks in many women. Sex-specific thresholds caught more of them.
Diagnosed years later
A University of Copenhagen study of 6.9 million people found women were diagnosed later than men across 770 diseases, including about 2.5 years later for cancer and about 4.5 years later for metabolic diseases such as diabetes.
None of these are rare conditions. They are sleep, heart health, cancer and metabolism. If the gap shows up there, it shows up in the everyday hormonal questions women bring to their doctors too.
Part 4: "Women" is not one data point
Including women in studies is step one. Step two is recognizing that a 24-year-old mid-cycle and a 44-year-old in perimenopause are not the same research subject.
Hormones change across the month and across a lifetime
A woman's estrogen and progesterone shift week to week across her cycle, and shift again through her 30s and 40s. Treating every woman as one averaged participant erases exactly the variation that defines female biology. The rete ovarii research is a reminder: the mouse study found genes in the structure that switch on as estrogen peaks. Timing matters.
Perimenopause starts earlier than most people think
A study from UVA Health and Flo found that 55.4% of women aged 30 to 35 already reported moderate or severe symptoms associated with menopause on a standard rating scale. Most women don't seek treatment until 56 or older. Psychological symptoms such as anxiety and irritability tended to show up years before physical ones.
A 2026 Mayo Clinic study of more than 17,000 people across 158 countries noted that perimenopause can begin in the 30s, yet researchers have studied it far less than menopause. Fatigue, mood changes and sleep problems were central to people's experience.
The funding still doesn't match the need
Women spend an average of 9 years in poor health, 25% more than men, according to the National Academies. Yet in 2023, women's health research received less than 8% of NIH grant funding, about $3.4 billion of $43.7 billion.
Specific science means asking specific questions: which life stage, which cycle phase, which symptoms, and which outcomes women actually care about.
Part 5: Why Libré builds for women, specifically
The supplement aisle inherited the same habit as medicine: one formula, one dose, one imagined average body. We think women deserve better than that.
Generic isn't neutral
When research defaults to men, products built on that research do too. A "one-a-day for everyone" formula quietly assumes everyone's body works the same way across the month and across the decades. As Parts 3 and 4 show, that assumption has a track record.
What we do differently
Physician-developed. Libré was co-founded by Dr. Nor Kara, and our formulas start from women's physiology rather than a unisex template.
Built around life stage. Daily Vitality is designed for everyday hormonal balance support. Life Transition Hormonal Blend is designed for the shifts of perimenopause, the stage Part 4 shows is still badly understudied.
Honest about evidence. Like the rete ovarii researchers, we try to be clear about what's known and what's still being learned.
What we're asking of science
Enroll women at every stage, from early adulthood through perimenopause and beyond.
Analyze results by sex, not just include women and average them away.
Track cycle phase and life stage as real variables.
Fund the questions women actually ask their doctors.
Stay curious about the parts of the female body we wrote off too early.
The bottom line
It took 150 years for science to ask what a structure attached to the ovary actually does. Women shouldn't have to wait that long for the next answer.
The rete ovarii story isn't really about one tiny tube. It's about a habit: assuming the female body is either the male body with extras, or too complicated to bother with. Both assumptions cost women time, money and health.
Michelle Wolf is right to be annoyed. So are we. The fix isn't outrage alone. It's research that studies women specifically, reports results for women specifically, and builds products for women specifically. That's the standard Libré holds itself to.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for education only and is not medical advice.
Sources
Science News, "An overlooked organ may help the ovary function," April 2025
Totally The Bomb, Michelle Wolf and the rete ovarii, October 2026
Applied Clinical Trials, "Women and Trials: When Is Gender a Consideration?"
NIH Office of Research on Women's Health, history of women's participation
Zucker and Prendergast, Biology of Sex Differences, 2020 (abstract)
British Heart Foundation, heart attack misdiagnosis in women, 2016
