In October 1990, the economist Julian Simon opened a small envelope from California. Inside he found a check from the biologist Paul Ehrlich for $576.07. Ehrlich didn't include a note.
Ehrlich had published The Population Bomb in 1968. He opened it with the line "The battle to feed all of humanity is over," and he predicted that hundreds of millions of people would starve to death in the 1970s. Simon thought Ehrlich had people backwards. Ehrlich saw each new person as another mouth to feed. Simon saw each new person as another mind that might work out how to feed everyone else.
In 1980, Simon challenged Ehrlich to put money on it. Ehrlich and two colleagues chose $1,000 worth of five metals: chromium, copper, nickel, tin and tungsten. If people were running out of them, buyers would pay more in ten years. By 1990, buyers paid less for all five after adjusting for inflation.
I'll be fair to Ehrlich. Simon chose a lucky decade, and analysts who rerun the bet over 1980 to 2011 find that Ehrlich would have won on four of the five metals. But Ehrlich lost on his bigger claim. Norman Borlaug and his colleagues had already bred high-yield wheat, farmers across Mexico, India and Pakistan planted it, and the Nobel committee gave Borlaug the Peace Prize in 1970. People still died in famines, mostly where armies and governments kept food from them. Nobody saw the global die-off Ehrlich had promised.
Most of us have taken Ehrlich's side of that bet with our own lives, and we pay in years instead of dollars.
TL;DR: People who expect the future to go badly put off the family, the company and the work they want most. They've expected wrong for 200 years. If you want a family, have one, and build something that other people will keep going after you.
You're already placing the bet
In 2023, Gallup asked Americans how many children make the ideal family. Forty-five percent said three or more, the highest share since 1971. In 2024, American women had fewer than 1.6 children each on average, the lowest rate the CDC has recorded.
Americans tell pollsters they like big families, then have small ones. Ask them why and they name money, housing, timing and the planet. People who give those reasons usually assume the next 30 years will go worse than the last 30.
People apply the same forecast to everything else. They put off the company until the economy settles, the house until rates drop, and the move until the news gets calmer. One day they turn 45 and find that they planned around a calm year that never came.
Answer this question in writing:
"If I knew for certain that the next 50 years would go better than the last 50, what would I do differently starting Monday?"
Your list shows what you give up by expecting the worst. Keep it.
Check your forecast against the record
Hans Rosling and his team at Gapminder asked people in many countries a simple question: over the last 20 years, has the share of the world living in extreme poverty almost doubled, stayed about the same, or almost halved? In the United States, only 5% picked the right answer, "almost halved."
Here's what people did while most of us weren't looking:
- Child deaths. Around 1800, more than a third of children died before their fifth birthday. Today, fewer than four in a hundred do.
- Poverty. In 1990, about 2.2 billion people, roughly two in five, lived on less than $3 a day. By 2025, about 830 million did, roughly one in ten, even though the world had added nearly 3 billion people.
- Lifespan. A child born today can expect to live about twice as long as a child born in 1900.
Most people miss this because editors sell fear. Readers click on disasters, so editors run disasters. When you read a headline, remember that an editor chose it to keep you scrolling.
I'm not asking you to ignore real risks. People face real dangers from climate change, pandemics and powerful AI. The physicist David Deutsch sums up his view in two short sentences: "Problems are inevitable. Problems are soluble." People solve problems, and we'll solve more of them with more people who are well fed, well educated and willing to try.
The three best arguments against having kids, and my answers
The strongest objections I've heard:
1. "Having a child is the worst thing I can do for the climate."
Young people take this seriously. In a 2021 survey of 10,000 people aged 16 to 25 across ten countries, published in The Lancet Planetary Health, 39% said they hesitated to have children because of climate change.
Many of them have seen the claim that one fewer child saves 58.6 tonnes of carbon dioxide a year. Seth Wynes and Kimberly Nicholas published that number in 2017, and they built it on a 2009 study by Paul Murtaugh and Michael Schlax. Wynes and Nicholas took their figure from the scenario in which every descendant of yours keeps emitting at 2005 rates indefinitely. When Murtaugh and Schlax instead assumed that people cut emissions to half a tonne per person per year by 2100, the carbon cost of each child fell by nearly 90%.
People are already making those cuts. Britons emitted less greenhouse gas in 2024 than in any year since 1872, and they cut emissions by 54% from 1990 while their economy grew by 84%. Between 2010 and 2019, engineers and manufacturers cut the cost of solar electricity by more than 80%. If you want your child to leave a small footprint, help build cleaner energy and vote for the people who'll fund it. Your child might grow up to help build it too.
2. "We can't afford it."
Sometimes that's true, so run real numbers instead of guessing. Isabel Sawhill and her colleagues at Brookings estimated that a married, middle-income couple would spend $310,605 to raise a child born in 2015 through age 17, or about $18,000 a year.
That's serious money. But families pay it monthly over 17 years, and Sawhill's team based it on what middle-income families spend on average, which isn't the least a family can spend. Families on lower incomes spend less, and many of them raise happy kids. Many governments also pay parents through tax credits and child benefits, so look up what you'd actually receive. If housing costs stop you, go to your city's zoning meetings and speak up for more homes. Voters set those rules, and voters can change them.
3. "I'm not ready."
Ask ten parents whether they felt ready. Most will laugh. People learn to be parents by being parents.
If you don't want kids, don't have them. You owe no one a child. You can propagate in other ways.
Build things that other people will keep running
To propagate means to spread something forward: plants, ideas, skills, companies, people.
Andrew Carnegie paid to build 2,509 public libraries between 1883 and 1929. He attached a condition to every gift. The town had to provide the land and promise to spend a tenth of the building's cost every year to run it. Carnegie built libraries that only worked if the townspeople kept them open, and many towns still do.
You can work the same way:
- Start the company, then hire people who'll go on to start their own.
- Teach a skill that took you 15 years to someone who can learn it in three.
- Write the book or record the course, and leave good instructions behind.
- Build a community, then hand it to the people who'll run it after you.
When you get stuck, ask Tim Ferriss's question: "What would this look like if it were easy?" Most people stall because they try to plan the whole project before they take the first step. Ask what an easy version would look like, and you'll usually find a step you can take this week.
Fear-set your biggest decision
Seneca wrote to his friend Lucilius almost 2,000 years ago: "We suffer more from imagination than from reality." Ferriss built his fear-setting exercise for hard decisions around that line. Pick the decision you've put off longest, whether that's having a child, quitting your job or starting the thing. Then take three pages.
Page one: the worst case. List everything that could go wrong. Next to each item, write what you could do to prevent it, and what you'd do to repair the damage if it happened anyway.
Page two: the upside. Write what you'd gain from trying, even if you only partly succeed.
Page three: the cost of waiting. Write what staying put will cost you in six months, one year and three years, in money, health, relationships and regret.
Most people finish page three and realize they've spent years pricing the risks of acting while ignoring what they lose by waiting.
The seven-day protocol
- Skip the news for seven days. Ferriss has recommended this low-information diet since The 4-Hour Workweek. Your friends will tell you about anything big.
- Read one long-view book. Start with one from the list below.
- Do the fear-setting exercise on the decision you've put off longest.
- Have the conversation. If you've avoided talking to your partner about kids, talk about it this week, and bring numbers instead of moods.
- Teach one person one thing. Pick someone younger than you and give them an hour. Show them how you do the work, and let them try it while you watch.
- Plant something. I mean this literally. Put a tree, a tomato or a pot of basil in the ground and watch it grow.
- Take the first step on your Monday list. Pull out the list you wrote at the start. Pick one item, then do the first small part of it before the week ends.
Further reading
- Factfulness by Hans Rosling, Ola Rosling and Anna Rosling Rönnlund
- The Beginning of Infinity by David Deutsch
- The Bet by Paul Sabin, the full story of Simon and Ehrlich
- Tim Ferriss's TED talk, "Why you should define your fears instead of your goals"
- Our World in Data, for checking any number you see in a headline