Does Stagnant Male Income Explain Falling Fertility and Marriage?
Mostly Agreeing With Lyman Stone's hypothesis
Sociologist and demographer Lyman Stone has a recent post out on How to Raise Fertility. The post begins with a graph from John Burn-Murdoch’s recent FT piece showing that there is a global trend in falling marriage rates in sync with falling fertility.
Lyman then makes two claims:
1. The biggest reason marriage is falling is male economic underperformance.
2. While we try to find solutions for that issue, in the meantime, marriage subsidies work very well.
Lyman proposes a theory that connects male economic performance and marriage rates through male income acting as an insurance policy for their partner. This is different than being providers of income: women today have high incomes on their own. But they also know that if they have a child, they will certainly face a short term shock to their income and possibly a much longer term one. A high earning partner can smooth out consumption during these periods like an insurance policy would. This is a believable theory for why male income might be important for marriage rates and especially important for follow-on fertility.
Next, Lyman shows some correlations between male’s income changes and female’s fertility changes or marriage rates in the US. For example, he shows that the male age groups with the weakest income growth are young men and, correspondingly, that the female age groups with the fastest fertility decline are young women. Then, he shows that states with higher young male income growth had larger increases (or smaller decreases) in marriage rate.
There are two issues I have with this analysis. First and foremost is a lack of global data. Fertility and marriage decline are global trends, so that's the first place one should look to disprove a theory. Lyman acknowledges this problem but doesn’t rectify it. It is hard to believe that young male income is falling in all of the countries where John Burn-Murdoch documents marriage decline. Take Turkey for example, whose marriage rate declined by nearly 30 percent since 2000. I couldn’t find income by age group data, but over this period Turkey’s GDP per capita increased by 330% all while female labor force participation was below 35%. It doesn’t pass the sniff test that young male income would be falling under these conditions and yet Turkey’s marriage rate is falling.
The second problem is that falling young male income is a relatively recent phenomenon but falling fertility is not. All of the countries plotted below had rising young male incomes for most of the graphed period, but fertility rates declined nonetheless.
Indeed, this is something John Burn-Murdoch points out in his piece. Most of the fertility decline in the past is explained by married couples having fewer children, and only recently it has started to be caused mostly by fewer marriages. This is actually a piece of evidence in favor of Lyman’s first claim that stagnant male incomes explain the more recent decline in marriage, but it cuts against the claim in his title that this is “How to Raise Fertility.” If most of the fertility decline in the past wasn’t caused by low male incomes or falling marriage rates, then we won’t fix most of the fertility decline by reversing these trends.
I don’t have any problems with the arguments Lyman makes for his second claim, that marriage rates can be boosted by subsidies. He links to compelling evidence from lottery winners showing that a wealth increase leads to higher marriage rates and fertility rates for men. The fact that a completely untargeted wealth subsidy can significantly increase marriage rates is strong evidence that a more targeted marriage subsidy would have even larger effects.
So I basically come away agreeing that subsidizing marriage is a promising and high leverage first step to at least stave off further decline in fertility at least in the US and other western nations. It probably isn’t enough to recover to early 20th century TFRs since earlier fertility decline wasn’t due to falling marriage rates, but maybe getting our heads above water at a TFR of 2 is what’s most important anyways. There is also a chance that more married couples cause downstream cultural changes that can raise fertility beyond the static effect that one would predict from more marriage.
A few points:
1) I think age at first marriage for the bride is a really important causal variable for fertility rates. There is a huge difference in the number of children that a married couple can have when the bride is age 23 versus age 30. I am not claiming that it is the only causal variable, but it is perhaps the most important and it is often not mentioned at all.
2) Regarding subsidizing marriage, I think most proposals to do so are sorely lacking. My proposal for a Working Family Tax Credit is designed to promote upward mobility but it may also have a positive impact on fertility. It also indirectly boosts male income after marriage.
https://frompovertytoprogress.substack.com/p/the-case-for-a-working-family-tax
3) I don’t think that it is male income that is the key variable so much as young male income compared to other adult workers. We have seen increased income for middle-aged people to a much greater extent than younger workers, likely because employers demand more experience and skills that young people do not yet have.
And it may be young male income compared to young female income that is a key causal variable.
The decline in fertility has many drivers, thus improving it will almost certainly need multiple solutions.
some are good, birth control allowing people to not have unplanned pregnancies is good.
But most are bad.
One cause that I think a lot of people don't know about is declining sperm levels. Over the last 50 years men have lost over 50% of their sperm levels AND they are still declining. This is a huge problem not getting enough press. Shanna Swain's excellent book "Count Down" is a great in depth read on this topic. She's also covered it in numerous podcasts
https://www.shannaswan.com/countdown
After that I think the next big driver is how long it takes for couples to feel like they are in a good place to have kids. For example, I met my wife when I was 25, she was 23. We married 2 years later. We were living in an apartment and both agreed we wouldn't have kids until we were in a house, we stayed in the apartment for an additional 2 years trying to get ahead before finally moving in with my parents to save up money to buy a house. Did that for another 2 years, before finally buying a house. Now I'm 31.
Couple years later, we start trying, had a miscarriage then a 2nd one. Finally had our first kid when I was 37, our second when I was almost 40. My wife was now 38, and we were done.
If we had been able to have kids earlier we almost certainly would have had another one, maybe 2.
I strongly believe we need to bring down housing costs by building a LOT more housing. In our area you could buy a track start home for $100k in the late 90's. Now they are going to $600k.
Incomes didn't increase by 6x.
We need to make it easy for families to get started, This would also make it easier for families to get buy on one income for a while. Also certainly a factor.