Fertility Cliff
Radiolab
12/26/25
•26m
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As she -- and her friends — approached the age of 35, senior correspondent Molly Webster kept hearing a phrase over and over: “fertility cliff.” It was a short-hand term to describe what she was told would happen to her fertility after she turned 35 — that is, it would drop off. Suddenly, sharply, dramatically. And this was well before she was supposed to hit menopause. Intrigued, Molly decided to look into it — what was the truth behind this so-called cliff, and when, if so, would she topple?
This story first premiered in “Thirty Something,” a 2018 Radiolab live show that was part of, Gonads, (https://radiolab.org/series/radiolab-presents-gonads)a six-episode audio and live event series all about reproduction and the parts of us that make more of us. The live event was produced by Rachael Cusick and edited by Pat Walters.
Special thanks to epidemiologist Lauren Wise, at Boston University. Plus, Emily, Chloe, and Bianca. And of course, Jad Abumrad.
If you’re more of a visual person, here are the graphs we explain in the episode, we also include links to the corresponding papers in our Episode Citations Section, below!
LINK TO GRAPHS:
https://media.wnyc.org/i/1860/1046/c/80/2025/12/FERTILITY_AGE_GRAPHS_1-4.jpg
EPISODE CREDITS:
Reported by - Molly Webster
Produced by - Arianne Wack
Fact-checking by - Diane A. Kelly
EPISODE CITATIONS:
Audio:
- Gonads (https://radiolab.org/series/radiolab-presents-gonads/)
A six-part audio series on reproduction and the parts of us that make more of us - The Menopause Mystery (https://radiolab.org/podcast/the-menopause-mystery)
One of Radiolab’s most listened-to episodes of 2025!
Videos:
“Radiolab Presents: Thirty Something”
https://youtu.be/LOJVAaSwags?si=czCBraHf1JEqmAQi
Research Articles:
- Graph 1: Can assisted reproduction technology compensate for the natural decline in fertility with age? A model assessment (https://zpr.io/ft6dqdbkJnTd)
- Graph 2: Ovarian aging: mechanisms and clinical consequences (https://zpr.io/GrPLebynpvxV) , Brookmans, et al.
- BUT, the graph was borrowed and actually comes from this 1991 paper, Delaying childbearing: effect of age on fecundity and outcome of pregnancy” (https://zpr.io/whWg2UAZsb6h)
- BUT, the graph was borrowed and actually comes from this 1991 paper, Delaying childbearing: effect of age on fecundity and outcome of pregnancy” (https://zpr.io/whWg2UAZsb6h)
- Graph 3 and 4: Age and fecundability in a North American preconception cohort study, (https://zpr.io/Rmqry4Kd67hY) Wise et al; Dutch fertility research
Further reading:
Predicting Fertility, (https://zpr.io/YEdfiYT29rUh): Magazine article on Lauren Wise’s research,
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•35m
In 1971, a red-headed, tree-loving astronaut named Stu ‘Smokey’ Roosa was asked to take something to the moon with him. Of all things, he chose to take a canister of 500 tree seeds. After orbiting the moon 34 times, the seeds made it back to Earth. NASA decided to plant the seeds all across the country and then... everyone forgot about them. Until one day, a third grader from Indiana stumbled on a tree with a strange plaque: "Moon Tree." This discovery set off a cascading search for all the trees that visited the moon across the United States. Science writer, and our very own factchecker, Natalie Middleton (https://www.nataliemiddleton.org/) tells us the tale.
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EPISODE CREDITS:
Terrestrials was created by Lulu Miller with WNYC Studios. This episode was produced by Tanya Chawla and sound-designed by Joe Plourde. Our Executive Producer is Sarah Sandbach. Our team includes Alan Goffinski, Ana González and Mira Burt-Wintonick. Fact checking was by Diane Kelly.
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Our advisors for this show were Ana Luz Porzecanski, Nicole Depalma, Liza Demby and Carly Ciarrocchi.
Support for Terrestrials also comes from the Simons Foundation, the Arthur Vining Davis Foundations, and the John Templeton Foundation.
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Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today.
Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing radiolab@wnyc.org.
Leadership support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.
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