If you want to increase fertility, look at how religions do it
People may want to increase fertility for different reasons. Statists because the power and influence of states is linked to their total population; progressives and policy-makers, to help make welfare states sustainable; utilitarians because they think most human lives are good in themselves; religious people because family and childrearing are religiously important; liberals who believe that people are having fewer children than they want; longtermists who worry that humanity might die out completely. As a result, there’s an on-going debate about how to raise fertility.
What’s odd about this debate is that it focuses mostly on what states can or can’t do to raise the Total Fertility Rate (TFR) — mostly on what they can’t do, because state policies do not seem to be very effective. For example, here’s the excellent Yaw on Hungary’s fertility policy:
Equivalent to 6% of Hungary’s GDP is spent on family policies in direct outlays, subsidized loans, and forgone tax revenues… After this massive investment, Hungary still has a lower TFR than the United States which doesn’t pursue any of these policies.
In short, after over a decade of intense spending and social engineering, Hungary's fertility still remains well below replacement.
The academic literature on fertility policy is not quite so negative: this recent literature review suggests that parental leave policies and childcare subsidies can increase fertility. But still, as Yaw puts it: “No developed country has successfully spent its way back to replacement-level fertility.”
(One possible exception is two state policies that were not designed to affect fertility, but seem to have large effects decreasing it: state pensions and easier divorce. State pensions reduce the incentive to have children to support you in your old age; easy divorce makes it riskier to partner up and have children. But no state is yet considering reversing these policies for fertility reasons.)
The chart below makes the point visually: no Western or Asian developed country has above-replacement fertility.1 All the existing variation between these countries is between a TFR of 1 and 2.
Why do I say this focus on state policies is odd? Because there are groups which, while exerting far less power than states, do much more to affect fertility rates. They are, of course, religions. Here’s a picture of religious TFR globally.
Of course this includes places in developing countries which still have above-replacement fertility: but the point is that the variation is very large. The difference between Unaffiliated and Muslims is about twice the absolute difference in TFR between the highest- and lowest-fertility developed country. Even the difference between Unaffiliated and Christians is more than the difference between developed countries.
But you don’t have to look globally. Here’s a graph of fertility by religious attendance within the US:
The gap between weekly service attenders and the non-religious, in this one country, again spans more than the variation in all developed countries. The gap also seems to have grown since 2014, which is important if you think that new technology may be causing fertility to drop.
Religions can’t tax, yet they induce more variation in fertility than states do with all their powers. One can look at this two ways.
If I were a policy-maker, I would focus on trying to understand how (some) religions successfully maintain fertility, rather than trying to understand states’ unsuccessful attempts to keep fertility above replacement.
If you are more pessimistic about the capacities of contemporary liberal-democratic states to deal with new policy challenges, then you might reasonably bet that religions, not states, will be the collectives which maintain fertility in the future. (Of course, for that to be true, they will have to stop haemorrhaging members by conversion. But perhaps religions, or non-religions, which can’t reproduce themselves in the biological way will also struggle to stay attractive to new adherents.)
What do we know about how religions affect fertility? This 2004 paper by Kevin McQuillan suggests an answer: high fertility religions have norms bearing on fertility behaviour (not necessarily norms directly favouring of high fertility, but related to fertility behaviour e.g. norms about the status of mothers), plus the ability to back these norms with sanctions (not necessarily material ones, but e.g. reputation), plus they are central to believers’ identity. That all seems plausible, but it is also rather broad. It seems as if there could be much more work to unpack how contemporary religious groups do this.
The obvious exception is Eric Kaufmann’s Shall The Religious Inherit The Earth? This is a fascinating and deeply-researched book exactly on the topic of religious fertility. But it broadly views religious fertility as a danger for liberalism, rather than as something to learn from. Perhaps that is a mistake. Even if you don’t accept any religious world view wholesale, it may be worthwhile understanding what they are doing right.
The European exception on the graph below is the Faroe Islands. A genuine, but unplotted, exception, is Israel with TFR of 2.9.
People often talk at length about Israeli tfr in the context of the ultra orthodox, which often does come from patriarchal social norms, but that's not the full story. There is also a strong secular norm towards fertility; Israel is constantly at war and if they don't have enough children to form the next generation of the army, it will cease to exist.
This is theoretically true for every nation, but it's actually viscerally true for Israel, and is also often true for diaspora Jews; if you want Judaism to flourish and prosper by far the most impactful thing you do is be a woman and choose to have more children. The same is likely true for other religions, I know women of other religions with large families who are heavily independent and by no means patriarchally repressed, but are conscious that they are part of a community that can only continue to exist through the efforts of its members, and know they are in the strongest possible position to contribute