Freakonomics Radio
Hosted by Stephen J. Dubner
We are constantly wowed by new technologies and policies meant to make childbirth better. But beware the unintended consequences.
5,284 words · 8 speakers
Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.
Freakonomics Radio is sponsored by PNC Bank. Boring, great word, bad rep. Yet, time and time again, here at Freakonomics, we find that when something culture-changing happens, boring things like calculations and careful planning are usually behind it. Which begs the question, why not apply it to other aspects of life, like banking, for example? Well, PNC Bank did, since its inception, proving time and again that the best banking strategy isn't the exciting type, but the steady, reliable, definitely-not-yolo type. PNC Bank: brilliantly boring since 1865. Brilliantly boring since 1865 is a registered mark of the PNC Financial Services Group, Inc. PNC Bank, National Association, Member FDIC.
Freakonomics Radio is sponsored by hotels.com. Hotels.com helps you find and book the right stay for work faster. With business preferences, save your travel must-haves, like gym access or breakfast, just once, then get tailored results whenever you search for work-travel. Plus, with a free membership, you can save up to 20% on hotels and earn rewards on every stay for future travel. Book now at hotels.com. Visit hotels.com for details.
Freakonomics Radio is sponsored by Amica. You know what they say, if you want to go fast, go alone. If you want to go far, go together. So, go with Amica and get coverage from a mutual insurer that's built for their customers, one that looks after what's important to you together. Auto, home, life, and more, coverage that fits your unique needs. Amica helps you protect what matters most. Visit amica.com and get a quote today.
Freakonomics Radio is sponsored by ChatGPT. ChatGPT Work is a new way to work in ChatGPT. ChatGPT Work can pull info from across your apps and connect to your tools to help you create finished work. You can even automate work in ChatGPT with the Scheduled Tasks feature, and the whole time, you stay in control. Put ChatGPT to work on your most ambitious ideas and projects. Get started at chatgpt.com by selecting Work Mode, available on Plus and Pro plans.
Okay, mijn naam is Geert Jan Olsder. Mijn laatste naam is Olsder, gespeld als O-L-S-D-E-R. Mijn 867, wat in Nederland betekent dat je vertrok.
Bepreken hij vertrok. Geert Jan Olsder was universiteitfelle in toepassende mathematiek. In 1975 was Olsder 31 jaar oud. Hij en zijn collega's aan Twente Universiteit waren heel mooi. Ze dachten dat ze alles kunnen doen.
Het kwam simpelweg op. Waarom werken we niet aan populatieplanning?
Natuurlijk, populatieplanning. Wat anders zou een mathematiker moeten werken? Olsders crew verwachtte een islandnaar met geen emigratie of immigration, alleen geboorte en dood.
Het zag eruit als een mooi matematische probleem.
Het essentiële riddel was dit. Als de populatie oud en als de langzaamheid increased, wat was de juiste geboorterate om de island niet te overpopuleren? Olsder en zijn collega's werkten hard op het probleem en ze kwamen met een elegante ogenblik. Hun onderzoekspapier, dat heet: "Populatieplanning: Een bestreden tijdoptimal controleprobleem", werd gepubliceerd in een universiteitreport. Eén dag was Olsder in zijn kantoor met een collega.
En dan kreeg we een telefooncall van de centrale of main kantoor van de universiteit. En ze zeiden: "Oh, we hebben een groep Chinese mensen hier, wetenschappers. En apparaatlijk is er iets mis in de organisatie. We kenden niet over deze groep die komt. Maar ze willen dit avond geïnteresseerd worden. En er zijn twee mathematicers tussen hen. Zouden ze je departement welkken?"
Oké, dus er waren een paar visiteer Chinese wetenschappers op campus die bedragen babyzitting. Zou Olsder een van hen zorgen? "Zeker", zei hij. Hij ging hen naar een café. Ze kregen bier. Ze chatten over de universiteit, over het mathdepartement.
Maar na één uur of misschien een half uur ofzo. Ik bedoel, de gesprek stopt wat omdat, ik weet niet, door lank van interesse. Ik weet niet.
Vertel me, hoe kwam de gesprek naar het onderwerp van je papier over de matematiek van populatie?
That took a while. Because in the beginning, we were talking in general terms. I hesitated at the moment, shall I talk about this population planning paper?
Olster hesitated because his paper had to date only been published internally. He didn't want to risk getting scooped by another scholar. But, well, math is math and beer is beer. So Olster told this Chinese guest about his population paper.
And he took a lively interest. I mean, it seemed as if he thought at that moment already it might be something for us. I did not realize that at the time, but now that I look back and I see what the consequences were, I think that he was triggered by this kind of scientific work. And of course, he was just, just, I mean, between parentheses, a domino in a long series of dominos. And maybe I was also somewhere, the domino is right in the beginning and they all started falling. And ultimately, of course, the consequences were the one child policy in China.
The one child policy in China? Over beers in Holland? Who knew?
From WNYC and APM, American Public Media, this is Freakonomics Radio. Today, unplanned parenthood, misadventures in baby-making. Here's your host, Stephen Dubner.
1975. Two strangers, one Chinese, one Dutch, talk shop over a beer. And when the conversation stalls, the Dutch mathematician mentions a paper he's written on population control. "Hmm," says the Chinese visitor. "Might you be willing to mail me a copy of your paper?" "Sure," says the Dutch professor. Chin Chin. What Hert Jan Olster didn't know was that his visitor, Sung Jian, was a leading Chinese government scientist. His background was in missile science, but his research portfolio now included population control. In fact, he would go on to become one of the architects of the one-child policy that
China introduced in 1978, and he later credited Olster's research as an influence. Now, it's not as if the one-child policy wouldn't have happened had those two men not met back in Holland, but it's still pretty sobering to consider the unintended consequence of that chance encounter over a beer.
I was this butterfly who moved its wings, you know, and that causes a fly to move, and then you get a little pebble that moves, et cetera, and ultimately you have a hurricane. Maybe I was one of the starters of this process, but purely by accident. I could not have realized at that time. So, I mean, if we could redo history, I mean, probably the same would happen again. Only one thing, you feel flattered, of course, if people take an interest in your research. My feelings about these consequences, I mean, how should I put it? Some people ask me, do you feel guilty? But I think that that's not the right question, because, I mean, the same could happen again nowadays under the same circumstances.
The one-child policy that Olster's research helped inspire is thought to have prevented roughly 250 to 300 million births in China since 1980. And given what you remember from biology class, you'd probably think that those never-born children would be about equally divided between boys and girls, right?
In most human populations, the natural sex ratio at birth is around 105 boys for every 100 girls.
And what is the most accepted explanation for why that ratio exists?
You know, it seems to be nature's way of ensuring a balanced population later on because it turns out males die at higher rates throughout their lives. And so by the time we reach adulthood, we have an equal number of males and females.
That's Mara Visten Dahl. For those of you keeping score at home, that's H-V-I-S-T-E-N-D-A-H-L because she's originally from Minnesota.
I am a Beijing-based correspondent with Science Magazine and the author of Unnatural Selection: Choosing Boys Over Girls and the Consequences of a World Full of Men.
When Visten Dahl first moved to China in 2004, she noticed something strange.
The fact that you could go to a school and look at a classroom in an elementary school usually, and you just see many more boys than girls.
And what did you do about it at first? Did you talk to the principal or the teachers and say, hey, what's going on? Are the girls being kept at home? Or did you kind of know right off what was going on?
Well, it crops up in the news from time to time that sex selective abortion has become very common in China. So that when women are pregnant, they get an ultrasound exam, and if the fetus turns out to be female, they abort. That's not all women by any means, but enough that there's a pretty significant gap in male and female births. So that appears in the news every time a new census comes out or a new survey, you see another article in the Chinese press reports on it as well as the foreign press. But the reasons why that gap existed aren't typically very well explained.
So for people who are aware of what are called the missing women problem, probably most of them are aware of that in large part because of, I guess, a paper that Amartya Sen wrote years ago, right?
Mm-hmm, 1990.
Okay. So kind of state for me his argument as best as you understood it coming into moving to China.
Well, Amartya Sen looked at the total number of women in Asia and compared it against the number of women who should, that should be there if the continent had a natural sex ratio. And in 1990, he found that there were 100 million women who were missing, who hadn't been born, but who should have been born. The natural sex ratio tells us that they should have been there. And he wrote a paper for the New York Review of Books, just pointing out this gap and the fact that this has happened at a time when China and India and other countries in Asia are developing very quickly. And, you know, really to say that we have to consider this when we look at development
and women and the fact that these countries are moving ahead and yet women are disappearing is, should be really worrying for us.
Vistendahl found that the overall boy-girl birth ratio in China is 121 boys for every 100 girls. In one city, Liyinggong, the ratio was 163 to 100. And it wasn't just in China. In India, the overall ratio was 112 to 100. According to one estimate, there are now more than 160 million missing women throughout Asia. That's about the same size as the female population of the US. Now, this gap is surely not all the result of sex-selective abortions. There's a lot of fatal violence against girls and women. Girls tend to have worse economic and educational and medical opportunities, but still, no
one can deny that in a lot of places, new parents have an overwhelming son preference. Now, why? There are probably a lot of reasons. Male children carry on the family name. They're considered more valuable to the parents because they can perhaps provide for the parents later in life. So I asked Vistendahl, is this decision typically an economic one?
You know, not entirely economic. I think there may be a more emotional reason as well. In my book, I actually don't go into these different reasons so much because I was really interested in how you get the same trend of many more boys being born than girls in this very wide variety of cultures.
Mm-hmm.
More boys than girls are born in China, India, also South Korea, Taiwan, Azerbaijan, Armenia, Albania, Vietnam. And, you know, these are places that have very different political traditions, some shared religions and cultures, but there's nothing that really binds them all together.
Nothing that binds these countries together, except for maybe one piece of technology. Yes, one piece of medical technology.
That's right.
Ultrasound.
Coming up, one piece of technology, 160 million missing women.
In some countries where sex selection has taken off, people see this machine as really a way to ensure them a boy.
From WNYC and APM, American Public Media, this is Freakonomics Radio. Here's your host, Stephen Dubner.
As we know, an ultrasound machine can be used to monitor a fetus in the womb to make sure the pregnancy is coming along all right. But since it was introduced in Asia in the 1980s, the ultrasound has also been used to determine the sex of a fetus and, if it's a female, have an abortion.
Over the past half century, the female-to-male gap in Asia has more than tripled. As Mara Vistendal tells it, this has changed how people view the ultrasound machine.
I visited an office of the Family Planning Commission in Anhui Province in China. And the Family Planning Commission is the entity that enforces the one-child policy. Today, they are actually tasked with dealing with the sex ratio imbalance a little bit as well. So they were talking to me about what they're doing to ensure that people have more girls and the various efforts they've been taking to make sure that the technology is used in the proper way. And they showed me to the room in their office where the ultrasound machine is kept. And they had actually installed two locks on the door, and no employee was allowed
to possess the key to both of them at the same time. There were two doorknobs, and it was called the two-lock system.
And the idea being that you need two separate employees to unlock these doors to use the ultrasound, under what conditions then? Under what circumstances then is ultrasound use OK in this office? Freakonomics Radio is sponsored by Granola. You know that moment when a meeting ends and someone says, "Let's circle back on this next week," and everyone nods but no one writes it down? Then next week rolls around and it's radio silence? That's why Granola exists. Granola is an AI-powered notepad built for the way real people actually meet. You take rough notes like you normally would, and in the background, Granola securely transcribes the meeting. Then it turns everything into clean, structured, actually useful notes when the meeting ends. And the best part? Granola works through your device's audio, which means it integrates seamlessly into
the video conferencing tools you already use. No setup, no awkward bots. It's just your normal meeting with superpowers. If meetings are eating up your day, Granola is a no-brainer. You can try it totally free. Just head to granola.ai/freakonomics. That's granola.ai/freakonomics to get your time back. Try it for free at granola.ai/freakonomics.
Freakonomics Radio is sponsored by Quince. You know those pieces in your closet that you find yourself wearing on repeat? The sweater that goes with everything? The perfect pair of pants? Or the tee you somehow always reach for first? Those are the pieces that make getting dressed easy, and that's what Quince does best. Quince focuses on high-quality wardrobe staples made with premium materials like 100% Mongolian cashmere, organic cotton, and merino wool. The styles are timeless, versatile, and designed to become the dependable pieces you reach for day after day. And it's not just clothing. Quince brings that same approach to everything they make, from hotel-quality bedding and bath to kitchen essentials and thoughtfully designed furniture. Find your next fall favorites at Quince.
Download the Quince app for app-exclusive offers or go to quince.com/freak. Get free shipping on your order and 365-day returns. Now available in Canada and the UK, too. That's Q-U-I-N-C-E dot com slash freak. Freakonomics Radio is sponsored by PNC Bank. Boring. Great word, bad rep. Yet, time and time again, here at Freakonomics, we find that when something culture-changing happens, boring things like calculations and careful planning are usually behind it. Which begs the question, why not apply it to other aspects of life? Like banking, for example?
Well, PNC Bank did since its inception, proving time and again that the best banking strategy isn't the exciting type, but the steady, reliable, definitely-not-YOLO type. PNC Bank: brilliantly boring since 1865. Brilliantly Boring Since 1865 is a registered mark of the PNC Financial Services Group, Inc. PNC Bank, National Association, Member FDIC.
Well, it's illegal in China to use ultrasound to determine the fetus's sex. So the idea being that if there's some oversight and two people are in the office at the same time, that they will somehow avoid breaking the law. I don't know if it works in practice, but what it suggests is that the ultrasound machine is viewed as a dangerous thing.
So what happens in a world with a surplus of men? For starters, there's more sex trafficking, more AIDS, higher crime rate. In fact, if you want to know the crime rate in a given part of India, one surefire indicator is the gender ratio. The more men, the more crime. Now, you might assume that sex selective abortion is a plague of the lower classes, where the economic penalty of having a girl might have the most sting. But that's not what Vistendal discovered.
It's high-income people who have access to new technology first. So when the ultrasound machines arrive, they are the first to use them. But at the same time, also, the birth rate has fallen pretty dramatically among upper classes and among educated people. And so when the birth rate drops, that puts pressure on a woman to make one of her two or three, one children, a son.
As it turns out, there's one particular kind of parent for whom this son preference is overwhelmingly strong. These are parents who are having a third child when their first two are daughters. In such cases, among these parents, sons outnumber daughters by 50%. And who are these parents? Yeah, they're Chinese, Korean, and Indian parents who've emigrated to the United States.
Now, the ultrasound machine didn't create this kind of problem, but it does enable it. Sun preference already existed, but along came a new birth technology that let mothers do something about it. Technology has consequences, often unintended ones. And so do laws.
So probably the most controversial finding I've ever had in economics was the argument John Donahue and I made that legalized abortion led to decreases in crime.
That's my Freakonomics co-author, Steve Levitt. He's a research economist at the University of Chicago. He was in the library one day, just leafing through the statistical abstract of the United States.
And I was shocked to see the number, a million abortions a year. And I thought to myself, you know, a million of anything is a lot, but abortion, I never would have imagined that abortion was so prevalent. But I didn't really have any sense of the scale, so I thought, well, how many births are there? And luckily, this book had everything in it, so I flipped a few pages forward, and I saw that there were only about 3 million live births in the United States each year. And then I thought to myself, 1 million abortions and 3 million live births? That means 1 out of every 4 pregnancies is ending in abortion? And that just seemed shocking to me. And I thought to myself, that's got to affect something.
Abortion spiked in the US after Roe versus Wade, the 1973 Supreme Court decision that made abortion legal in all 50 states. As Levitt thought, a number that big, 1 million abortions a year, 1 out of every 4 pregnancies, that's got to affect something. Now, he'd spent the past several years doing research on crime. His mind immediately mashed up his old research topic with this new one.
So what does this legalized abortion have to do with crime? Well, the argument's really simple, that there's enormous volumes of scholarship going back 50 years that suggests that unwanted children are at risk for crime. Basically, if your mother doesn't love you, nothing very good's going to happen to you in your life. It's also pretty clear that after legalized abortion became available, the number of unwanted children plummeted. So we see that the number of domestic children put up for adoption went way down. And in surveys, if you ask women whether they had unwanted births, those went way down as well. So those two simple pieces of the argument are all it takes. Unwanted children are at risk for crime, and after legalized abortion, the number of unwanted children went way down.
Therefore, after legalized abortion, crime should go way down if you wait 16 to 18 years to the point where that cohort exposed to legalized abortion actually becomes old enough to be in the criminal ages.
That was the theory, at least. And as Levitt found, the data backed it up. Roe v. Wade, a decision meant to increase a woman's reproductive control, was never intended to decrease crime in the US. But it did. Again, like the ultrasound, a natal development that had the most unintended of consequences. So you have to wonder, what's next? What's the next baby-making law or technology that we'll be talking about in 20 years? And who'll come up with it?
Well, in this case, the impetus was becoming a parent. You know, I think, like, everyone who becomes a parent, one can only marvel at how amazing it is to create a new life and watch it grow. But before your baby is born, it also can be a very nerve-wracking time.
That's Stephen Quake. He's a professor of bioengineering at Stanford. He's developed a new prenatal test, inspired by his own impending parenthood.
And in my case, because my wife was over 35 and we had our first kid, the doctors recommended amniocentesis as a form of prenatal testing to look for Down's Syndrome and things like that. And there's some risk associated with the test because a large needle goes right into mom's belly, right up next to the baby, to grab a few cells. And pull them out and both sort of going through the procedure and kind of the fretting while one waits for the results made a big impression on me and we went through this whole thing twice with two kids and so that got me interested in perhaps trying to think of ways to develop non-invasive prenatal diagnostic tests.
Now, just walk me through your thinking on this. You were thinking, you know what the procedure of an amnio is? It's taking a big needle, it's putting it into the mom, getting into the amniotic fluid very close to the baby, right? So there's some risk there, but then the reward is some early notification of potentially, you know, abnormal circumstances. How did you, as a scientist and as a father-to-be, go about thinking about the trade-off between the risk and the reward there?
Yeah, you know, it's a really difficult question and the way the doctors explain it to you, they say the risk of there being something wrong is about 1%. In other words, if you learn something from the test, that there's a genetic abnormality in the baby, that's about a 1% chance and the risk of losing the baby because of the test is also about 1%.
That risk of losing the baby as a result of amniocentesis made a big impression on Quake. He thought, there's gotta be another way. So he got to work on a simple blood test. It turns out that when a woman is pregnant, DNA from the fetus is floating in her bloodstream.
And so each molecule is voting for a chromosome and we're essentially looking for voter fraud, for slight over-representation of one chromosome relative to another. And so if the baby has Down's syndrome, there'll be slightly more chromosome 21 molecules in the mother's blood than every other chromosome.
Very good. So what you're talking about in a nutshell is... Instead of amniocentesis, which is an invasive and risky and expensive procedure, relatively expensive procedure, you're talking about a simple blood test to determine pretty much exactly what amniocentesis currently discovers. Is that about right?
That's about right.
Okay, so if there's a test, a blood test that's non-invasive, not dangerous, presumably, just about anybody who would be giving birth to a baby with Down's Syndrome could or would find out about it in time to do something about it. When we say do something about it, that's really euphemism for abort. Talk to me a little bit about that framework and what your test contributes to change that framework.
Sure. Well, let's take your euphemism for a moment, because I'll take issue with that. You know, it's a very, I think, personal and challenging question about whether to keep or terminate a pregnancy with Down's Syndrome. And there have been studies that have shown that for people who decide to take a Downs baby, determine, deliver the baby, the earlier they know the baby has Down's Syndrome, the more prepared they are to deal with it and sort of the lower the stress and the better the outcomes, both for the kid and the parents. And so, my argument would be, this sort of test adds value, whichever side of that debate you're on, whether you're going to keep the baby or terminate it.
The earlier you know, the better. And it's better for everyone.
And there are a lot of people who would argue that there is absolutely no reason in the world to terminate a Down's Syndrome pregnancy, that there is a strong population of Down's Syndrome advocates, parents, and people with it who say, yes, this is a syndrome, it's a set of challenges, a set of barriers, but not cause for termination. Do you have a position on that?
Yes, I do. And again, it's sort of a very personal one because it turns out one of my wife's cousin has Down's Syndrome. And, you know, I've known him for nearly 20 years from the time, I think, I first met him when he was four years old. And so, kids with Down's Syndrome are, you know, very interesting. They're warm and open and loving. And I can completely understand and sympathize with the argument to having a baby with Down's Syndrome and deciding not to terminate, having seen this kid grow up and what a wonderful kid he is.
Can you just blue-sky and imagine what some of the surprising or counterintuitive consequences might be of having such an easier availability of a blood test that can detect Down's Syndrome? Do you think there will rise up to be part of the population who says, you know what, the easier it is, then the more likely I am to not want to have it because I want what life and fate and order and God are going to give me. I don't know. I'm just wondering what you've thought through on that dimension.
Yeah, you know, it's, the overall goal here, I think, is to lower stress.
Uh-huh.
You know, impending parenthood is a very stressful time.
And you don't need to add a big needle to it.
That was kind of my motivation here. And so, you know, the hope is to make these tools available to people who want them and feel they'll lower their stress. And for people who don't want them, it's fine. You know, it's not something I want to impose upon the larger world. That being said, you know, if you want to think about blue-sky things, you know, we're not very far away from being able to sequence the better part of the fetal genome non-invasively. And so, you could learn many, many other things very early in pregnancy. And the question there is, do you want to turn that loose on the parents?
And on society, really, right?
And on society, exactly. And the answer is, I don't know. You know, I mean, it's just, it'd be horrible to think people were going to take some sort of action because, you know, their baby's eyes weren't going to be the color they wanted, or, you know, they weren't going to be as tall as they wanted. These are things you could presumably figure out fairly early on. And, you know, in practice, I think it is a self-correcting phenomenon. You know, it is challenging enough to conceive, especially these days, that people, I'm hoping, will not want to end it for trivial reasons. Because that's where I hope it's going to all equilibrate.
Stephen Quake's blood test, and another one like it, should be available quite soon. Now, how will parents respond? It's hard to say. The future is the future, and as we've argued here in the past, the future is hard to predict. But don't be surprised if we turn out to be surprised. There are a lot of powerful laws in the universe, but the law of unintended consequences may be one of the most powerful, especially when it's applied to something as intricate, as intimate, and as important as ushering a small new life into this big, old world.
Freakonomics Radio is produced by WNYC, APM, American Public Media, and Dubner Productions. This episode was produced by Susie Lechtenberg. Our staff includes Diana Nguyen, Catherine Wells, Borey Lam, Colin Campbell, and Chris Bannon. Our interns are Ian Chan and Dan Kedme. David Herman is our engineer. If you want more Freakonomics Radio, you can subscribe to our podcast on iTunes, or go to Freakonomics.com, where you'll find lots of radio, a blog, the books, and more.
Freakonomics Radio is sponsored by Ozempic. Innovation happens through rethinking what's possible, and when it comes to GLP-1s, Ozempic pill does just that. Learn more about Ozempic semaglutide tablets, 4 and 9mg, by calling 1-833-OZEMPIC, or visit Ozempic.com to view the medication guide and ask your doctor what's possible with FDA-approved Ozempic pill.
Freakonomics Radio is sponsored by Southern Company. The world and its energy needs are always changing. Southern Company's commitment to meeting this demand stays the same. That's because Southern Company believes energy is more than a utility. It's what powers possibilities. So they are looking ahead and investing $80 billion in infrastructure upgrades and are committed to fueling growth in ways that benefit all customers so that reliable and affordable energy is accessible for generations to come. Go to southerncompany.com to learn more. Southern Company, building the future of energy.
Hey, this is Will Arnett, host of Smartless. Smartless is a podcast with myself and Sean Hayes and Jason Bateman, where each week one of us reveals a mystery guest to the other two. We dive deep with guests that you love, like Bill Hader, Selena Gomez, Jennifer Aniston, David Beckham, Kristen Stewart, and tons more. So join us for a genuinely improvised and authentic conversation filled with laughter and newfound knowledge to feed the smartless mind. Listen to Smartless now on the SiriusXM app. Download it today.
This episode is brought to you by Charles Schwab. Is there a right time to sell a stock? Are you taking the right risks with your portfolio? Financial decisions can be tricky, and often your own cognitive and emotional biases can lead you astray. Financial Decoder, an original podcast from Charles Schwab, can help. Join host Mark Reapy as he offers practical solutions to help overcome the cognitive and emotional biases that may affect your investing decisions. Listen at schwab.com/financialdecoder.
Page updated September 30, 2026 · transcript and summary are machine-generated