High human capital fertility interventions

The fertility crisis Rosetta Stone

Modern society in action

If you want “the fertility crisis Rosetta Stone,” it’s right here:

From Geruso, Age and Infertility Revisited (2023)

Broadly speaking, when women wait til 27-29 to get married, and don’t start thinking about kids until 30+, they’ve thrown away more than half of their fertility.

According to this chart, the odds of a live birth in a given year at 20-22 are ~60%. The odds at age 30 are half that, ~30%, and at age 35 ~22%.¹

Why do women wait this long to think of marriage and kids?

For all the best reasons! To finish their education, to get established in their career, to take the time to find the right person and not “settle…”

I think simple unawareness may be a noticeable part of that, too. Not many people are actually aware of this curve. To the extent women think about biological clocks at all, I think they usually settle on something like “well, I should start trying to have kids before 40 if I want them.”

Of course, if you wait til 40, your odds of a live birth are now ~11% a year, a sixfold reduction, and your odds of Downs, autism, and other chromosomal abnormalities are all significantly increased:

All values approximate to ~10-15%, ie 1/500 could be 1/550 or 1/450

These are significant differences, and are a big deal overall. But I think most women aren’t aware of these figures. Men are equally ignorant, for that matter. And both genders should know this! I think charts like this should be talked about in health class in school, and that mothers should tell daughters, and that friends who know should share this knowledge with their friends that don’t, because it’s extremely useful and important info! I’ve shared this info with a number of friends of both genders by this point.

But the knowledge gap remains, and seemingly the great majority of men and women don’t feel the urgency that the data seems to argue for.

Overall, the problem is that marriage and kids are now seen as “capstones” that represent the peak of a life well lived, instead of “foundations” that you establish on the road to a life well lived.

I mean, I’m sure you’ve noticed that the people out there who are most amazing, talented, and thoughtful, who there should definitely be more of in the world, generally have between 0-2 kids - with FAR more at the “zero” end than is ideal.

This is totally a game of marginal kids

Do you know one thing that’s always amazed me about Singapore? I’ve spent a fair amount of time there, and everywhere you go, you see couples with babies! On the metro? In the store? Walking around town? Babies galore! Everywhere you look! Meanwhile, they’ve got one of the lowest fertility rates in the world! They actually recently clocked in at ~1.04 in 2023.

You’ll see the same thing in Tokyo, another famously low birthrate country (1.26). Tons of cute couples with babies. But Tokyo has an explanation, at least - all the young people come to Tokyo, and there’s a vast hinterland that’s basically all old people, so of course all the babies are concentrated in Tokyo.

But Singapore has no hinterland! It’s a city state! I used to think of it as THE biggest “statistical versus lived experience” gap I’ve personally seen.

But then while I was talking about this in an ACX comment thread once, some smart people pointed out that this actually fits the data perfectly fine if I’m mostly seeing single babies rather than families of multiple kids. A fertility rate of ~1 still means most couples have 1 kid! The REAL difference is that there are fewer multiple kid families.

And lo, this was indeed approximately the answer! There’s a much bigger “childless proportion,” and families are indeed smaller relative to higher fertility countries.

Women age 40-49 “completed fertility” 2019 data, so this is fertility for women born in the 70’s - obviously the trends are much worse for current generations

So how do you win, as a country? You win by moving people from the “childless” column to any other column, and by moving as many people as you can one column over, so they’re having more marginal kids.

Specific high income / education fertility gaps

More, this problem is concentrated in higher income and more educated women - it’s specifically a “high human capital” problem.

The gap between “ideal” and “realized” fertility among women of different cognitive ability - smarter women have bigger gaps:

You see similar trends by household income. Generally, the higher the HHI, the lower the birth rate:

Educational attainment is no different, where you go from ~2.7 kids for dropouts, to 1.3 - 1.5 kids for bachelors or graduate degrees:

Overall, we’re severely underperforming in terms of ensuring more of the next generation comes from smarter, higher income, and better educated parents.

But high human capital people are the ones you want to have more children, because most good things are driven by the top ~10%

Largely, most economic growth, company creation, patents, and technological progress comes from the top 10-20% of people in a given nation, and it gets more concentrated the more you go up. Arguably, something like 60-80% of “progress” is driven by the top 10% or better.

Ivy leaguers are only 0.5% of the people in the US - yet 20/21 presidents in the last 100 years have been Ivy leaguers. 100% of Supreme Court Justices. 41% of Senators, and 20% of House representatives. 50-60% of federal appellate judges, and 30-50% of state Governers and Cabinet members.

But it’s not just Ivy people!

60-70% of patent authors / holders have a graduate degree (usually in STEM fields), and STEM degree holders are 5-10x more likely to hold patents than non-STEM degree holders. Phd’s file 5x more patents per capita than bachelor degree holders.

Yet the percent of the US that has a graduate STEM degree is only 4-5%.

If you look at the unicorns of the last couple decades, the founders are generally Ivy educated, and from wealthy and connected families. Since just the Ivy league is “0.5% or better,” you can see the rough degree of concentration.

Bill Gates? Son of a wealthy lawyer and corporate board director, dropped out of Harvard.

Mark Zuckerberg? Son of a dentist and psychiatrist, went to Philips Exeter before Harvard.

Reed Hastings? Son of a lawyer, went to Stanford. His cofounder Marc Randolph came from a wealthy family, too.

Page and Brin? Both from academic families (computer science and mathematics Phd’s), studied at Stanford.

Jeff Bezos? Adopted son of an Exxon executive, went to Princeton, worked for D.E. Shaw.

Elon Musk? Wealthy and connected dad, U Penn and Stanford. And his mom was a model!

Sam Altman? Son of a doctor, attended Stanford.

Ilya Sutskever? Phd under Geoffrey Hinton, then postdoc at Stanford.

In fact, in general, if you look at normalized Rausch IQ scores versus problem difficulty, solving complex problems gets exponentially more difficult the harder the problem, and you need to go further and further out on the IQ and ability curve to have a chance of finding a solution.

“This means that for the hardest problems, ones that no one has ever solved, the ones that advance civilization, the highest-ability people, the top 1% of 1% are irreplaceable, no one else has a shot. It also means that populations with lower means, even if very numerous, will have super-exponentially less likelihood of solving such questions.”

We can see a similar trend in normalized IQ versus probability of inventing something, and even this likely underestimates it.

Hence, progress being driven most by the extremes of the bell curve in ability and IQ and background. These have all been <<1%-tier people so far. Now extend this out! Sure, this is the tippy top, but think of ANYONE you know who’s filed a patent or started a company or small business, or done something that impacted a lot of people positively. Odds are, they are smarter, more conscientious, more educated, and from wealthier backgrounds than average - and not just by a little, but by so much they’re likely in the top 5-10%.

Overall, you can see this top 5-10% of people are punching FAR above their weight when it comes to economic growth, company creation, patents, and technological progress, and in fact, this tiny slice of humanity is likely driving the overwhelming majority of those things.

This is exactly who you need more of! This is who EVERY country needs more of!

This is why it’s so important to think about and do things to increase high human capital fertility.

It’s not easy, it’s fighting a difficult rearguard action

But increasing fertility at all, even in entirely unfocused, aggregate ways, is an extremely hard problem.

To date, many countries have tried a wide number of interventions, ranging from:

• $10k bonuses per child (Singapore), or for 2nd / 3rd children (Russia)

• 3 years paid parental leave (France)

• 480 days paid leave at 80% wage (Sweden)

• Income tax exemption for mothers with 4 or more kids (Hungary)

• Free state paid child care (France, Germany, Sweden, Norway, Finland, Estonia)

• Free IVF (most EU countries)

• $750 / month payments per child (South Korea)

And essentially none of these have moved the needle. Often they don’t have any positive impact at all on rates, fertility still declines, but slower. The most any fertility intervention does if they are positive is to buff rates by ~5-10% or so for 1-3 years, after which fertility rates collapse and resume the same trajectory they were on before.

So the problem is HARD.

And it requires more expense and effort than just “give people a little money” for each kid.

Particularly for high human capital people, who earn more than average already, you’ll need to be thoughtful about aligning incentives, and the magnitude of incentives that might be required to have a real impact.

My favorite ideas on this front:

Because high human capital fertility is being driven down on multiple fronts, we should try positive interventions on multiple fronts:

1. Hypergamy - People complain women want hypergamy, because they won't "settle" and initiate 70% of divorces. So give the people what they want! Any guy who pays at least $100k in federal taxes in a given year has the legal right to have an additional wife. Now being seen with your hubby + other wives is a status symbol, and both genders love status symbols. Bring back harems! Plenty of women would rather be Bezos’ or Branson’s or Musk’s fifth wife than some regular dude’s first wife. End result: more high human capital kids.

2. Education - The educational Red Queen's Race is depressing fertility, because the competition to get into Harvard starts 6 months before birth, when you need to get on the waiting list for the right exclusive pre-school to give your precious Jaden a leg up, because if you don't get in there, and if you don't grind furiously and nonstop for the next 18 years, their chances of getting into Harvard are ruined! So on this one, you can't do much for the Ivies, but for each couple that's paid some threshold in taxes over so many years, guarantee a non-transferrable slot in an R1 for their kid. For California, this would be the UC's, inclusive of good ones like Berkeley, but lots of states have R1's. Suddenly some of the educational arms race is off, and you're guaranteed at least Berkeley and can pop out a few more kids.

3. Income tax - Federal income tax breaks for EITHER spouse for each additional biological kid, scaled so that if you have 6 kids, you pay zero income tax. It's a strong incentive to have more kids if either of you are high earners, including SAH mom plus high earning dad.

4. Brain trust bonuses - two STEM Masters holders get a $50k non-taxed bonus for each non-adoptive kid they have together. Two STEM Phd holders get $100k bonuses. Split the difference for a masters / Phd couple. Scale up or out as desired and as drives more incremental high human capital babies. Also extend it to those in the process of getting their Masters or Phd, because that’s them starting younger.

5. Child care - Greatly expanded and subsidized nanny / au pair programs in HCOL areas. You two are a "power couple" where you both make more than 6 figures, and have had at least 2 kids? Congrats! Have a free nanny / au pair! Daycare sucks - your kids can be picked on, they’re always getting sick, they get YOU sick all the time, and it’s really expensive for what’s basically babysitting. School-age hygeine knowledge and execution is likely better enough than daycare-age hygeine that it will materially reduce the amount of time everyone is sick if you have nannies until real school. A better experience for kids and parents! And at the margins, having free nannies for high performers should help incentivize extra marginal kids. Au pairs are already let in under the J-1 Visa, and that can be expanded at the federal level to whatever level we need.

6. Encourage age gaps² - - Given these fertility facts, what does a society that actually takes having high human capital children look like, culturally? On the male side, I think it would look like men being strongly encouraged to speedrun education³ and get established in the world, targeting being gainfully employed with enough income to support a wife and kids by the time they were 25. On the feminine side, if women were culturally encouraged to marry “established men” at eighteen to twenty and spend the next decade supported by their husband while raising kids and doing a slow exploration of their interests, with the goal of starting a fulfilling career at 30-35, I expect we would have a growing population and everyone could still use their full talents along lines of excellence in their lifetimes. Do you want to know how to best encourage this? Do the “income tax reductions per kid” as above, but it applies to the husband for 10 years, then it switches to the wife! It’s a much better “default” than the current “school, college, work” default path, on both fertility and quality of life fronts. It’s like “finding yourself,” but while having kids and building a family and a robust foundation with a higher status spouse to tackle the career you want most. This was actually the dynamic in the Baby Boom years! Men had higher incomes younger, and women married at 20-22 instead of 27-29 today. Age gaps were also about twice as high back then as they are today. I’m unironically going to bring this up several times as an option to my own daughters while they’re growing up (plus they’ll be growing up in an “age gap” household anyways, which hopefully helps).

7. The stick rather than the carrot - how much do you really care and want to move the needle? Childless adults could be made ineligible for all of a country's old age programs. SS and Medicare in particular are pay as you go, so your current contributions are paying for present-day retirees. If you didn't raise any kids to support your generation in retirement, you don't get the benefit. Seems unfair to poor people? I agree! Let’s make “the stick” ONLY happen for bachelor degree holders and higher, and have an income threshold. Surely, college degree holders making $100k or more a year can afford to save and fund their own retirement if they’re dead set on not having kids! You could even phase it in. You get 0% at 0 kids, 40% at 1 kid, and 100% at 2 kids. Heck, let’s say you get 120% of SS if you have 3! And these folks are generally good at math - let THEM figure out if “having SS and Medicare when old” is a big enough incentive to have some kids!

8. Free IVF - either with or without educational attainment and / or income criteria. If you need IVF, it’s probably because you’ve waited too long, per the opening fertility graph on this post. If you’ve waited too long, it was probably because you were getting educated and established in your career. Free IVF would help at the margins, and could lead to more high human capital babies. Although it hasn’t materially improved fertility rates in other places where it’s been tried, at the margins, and when coupled with these other interventions (particularly “the stick”), it’s likely to help.

9. Gengineering - it wasn’t covered here, but men grade female attractiveness on a bell curve, and women grade men pass / fail, and 80% of men fail. Whenever there’s a high standard most people are failing, the best solution is almost never “lowering standards,” what we need to do is use science and technology to increase the quality of men.

   For single factor pro-natalism, gengineering is the obvious answer here in terms of “the single biggest societal intervention you could enable to increase fertility.”

   Literally, all any country needs to do is make it legal - the market will take care of all the rest.

   Pretty much every woman that wants to have kids can, both historically and today. Furthermore, the amount of “lift” you can get to make them more desirable is really limited - men grade on a bell curve, and most women are desirable enough, so even if you pump a thousand micro-Helens of good genes into your daughters, there’s basically no grandkid difference, either individually or societally.

   But boys! Men suck! They’re too short, they’re too fat, they don’t earn enough, they’re dumb, they lay around all day playing video games, etc.

   If you start pumping height and myostatin inhibiting and intelligence and ambition and other great genes into your BOYS, that’s where the real grandkid lift lives! Women are harsh graders, and lowering standards is almost NEVER the right answer - literally use science and technology to raise men to a higher standard!

   Make men so good they’re literally a superstimulus like Tik Tok or junk food! And be sure to install the “wants a lot of kids” genes into them.⁴ That’s almost certainly going to move the needle, and takes advantage of Red Queen’s Races and status games in a way that will increase fertility for once, instead of lowering it.

1. Why is this noticeably lower than the usual fertility numbers you see?

Because most fertility numbers are hot garbage, based on small samples and highly selected populations, and / or from old data. The majority are based on Menken et al’s Age and Infertility (1986), in which he surveys Hutterites in the 1920’s, Geneva bourgeoisie in 1600-49, Canadians 1700-30, Normandy 1760-90, Norway 1874-76, Iran 1940-50, and Americans in the 1930’s.

So, limited data from vastly different time periods than today, in a profoundly different environmental, pollution, and diet regime.

Many more recent (2000+) numbers are from the European Study of Daily Fecundability, in which 782 couples were tracked for a couple of years, and the resulting 487 pregnancies in the study period were used to build a statistical model with similar age curves as Menken et al created.

Why is Geruso Age and Infertility Revisited (2023) better? They combine nationally representative data from 62 low and middle income countries that span Africa, Eastern Europe, Latin America, and Asia, with a 2.8M women sample size, and then use that to calculate a true “fecundability” curve using only women who are married, not on contraceptives, not currently pregnant or breastfeeding, and having periods.

Why is this better than the European study? The participants are a highly selected population (Europeans age 18-40 who specifically eschew contraception and never use condoms, and attend “Natural Family Planning” centers, from which they were recruited. Additionally people who were known to be infertile were specifically excluded, as well as anyone with any illness that might affect fertility. 66% of them had had a past pregnancy before study enrollment - a reasonable estimate of the amount of EU women who’d had a pregnancy by the average age in this study (28-30) is more like 50%.

In other words, they were specifically selected to be a known and higher fertility sub-population.

And honestly, even Geruso (2023) is likely over-estimating Western fertility, which is affected by obesity, diabetes, and metabolic diseases at a much higher rate than the developing world.

2. I’ve always been mildly astonished that age gaps aren’t way more common than they are, because:

Age gaps are the smart thing to do for both sides

For men: You get 3x higher fertility, women in their early 20’s are objectively the most attractive according to ALL men, you can share all the experiences and things in life you love most with them and it will all be brand new for them and you can relive that freshness and joy, and much more. When it comes to how men actually think and feel in private vs acting in public, men prize youth and beauty above much else, more or less. When it comes to actual behavior, they get more realistic - the first ones are literal attractiveness ratings, the second one is age range specified in dating profile. But that internal drive is for good reasons if you actually want kids (given the 3x fertility thing), and even if you didn’t want kids, it’s still a bone-deep drive in your evolutionary programming, because the ancestors who had that drive had a lot more kids!

For women: Older men are richer, wiser, treat you better, are better in bed, know more about the world, have a bigger trove of “known awesome experiences” to introduce you to, and will appreciate you more than a guy your own age.

Run this thought experiment: everyone wants a high status mate, right? Let’s take two similar 9/10 status guys - one is 20, and one is 40. They’re both fit and smart and good looking and thoughtful, they both dress well and smell nice and have stylish haircuts. The 40 year old would usually be richer and make more money, but let’s ignore even that for now, let’s make them both have a trust fund of roughly the same size. Now, which of these guys is going to treat a hot 20 year old woman better? The 20 year old guy is going to treat her much worse, is more likely to sleep around due to higher hormones and more opportunity and a more party-adjacent lifestyle, and is way less likely to marry her. The 40 year old is going to appreciate her more and treat her better, and is way more likely to marry or have kids with her. I’d seriously actively recommend dating with an age gap to my own daughters because of these things (although probably more like a 10 year gap vs a 20 year gap).

You’re worried that older people are noticeably fatter and uglier? Good news! You can choose only the silver-foxiest older men, who have taken care of themselves, and are still attractive and fit. Being fit and attractive even while older (contrary to the overwhelming norm) is also a direct and impossible-to-counterfeit sign of higher quality genes that will go into any kids you two have!

Would you *really* say no to this?

3. One of my biggest gripes about education is that there aren’t enough ways to test out and skip ahead. This should be WAAAAYYYY more legible and common than it is today (1% of students do it today). Like, it should be the default - they should test you at the beginning of every year, and put you in the appropriate grade level or classes based on those tests. Also, tracking should be ubiquitous, and there should be much more funding allocated to gifted and talented and magnet schools. It’s scandalous that on the coasts there are ~10x as many kids who can pass the tests as there are slots in gifted and talented and magnet schools.

But back to fast tracking education - I skipped grades in K-12. I CLEPPED ~32 credits in undergrad because I was outraged they wanted me to waste my time in gen eds that were so pointless “attendance” was part of the grade. And that was STILL not nearly enough! The entirety of school through undergrad was STILL at least 80%+ wasted time and BS for me.

They fight you tooth and nail about skipping grades - only about 1% of kids actually skip a grade - but a Johns Hopkins study estimates 2/7 kids could do it and benefit from it. Literature reviews (Miravete 2022) have also shown that "Grade skipping has a positive academic impact and, in most cases, a positive or zero psychosocial impact." - after all, if you’re already in a significantly different mental space than your chronological peers, it’s not like you’re going to be doing all that great socially if you stay in the slower, more boring class, either.

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