Posts tagged Fertility
Freeze the eggs!

Global birth rates are falling at an accelerated pace. According to the UN, the global total fertility rate (TFR) dropped to a record low of 2.25 in 2023 and is projected to fall further to 2.2 in 2024. At this pace, the TFR is set to dip below the replacement level of 2.1 nearly two decades earlier than the UN’s latest forecasts had anticipated.

The long-run decline in fertility has two main components. The first is the "quantum effect"—the trend for families to have fewer children as incomes rise, choosing instead to invest more in each child, particularly through education. Economics and evolutionary theory both rely on this shift in the quantity-quality trade-off to explain why fertility has fallen since the Industrial Revolution, even as wealth has grown.

The second component is the "tempo effect"—birth postponement. Women are delaying motherhood due to rising labour force participation and career opportunities, which increase the opportunity cost of having children, and shifting social norms. Other contributors include difficulty in finding a partner, precarious housing and job markets, and evolving personal preferences. Meanwhile, outright childlessness is increasing, which neither the quantum nor tempo frameworks fully explain.

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Falling global fertility, how far and how fast?

It has been a while since I last delved into one of my favorite topics: global demographics. In this piece, I revisit the subject by examining high-level data on key global demographic indicators from the UN’s July 2024 Population Prospects database. I will begin with birth rates.

Scarcely a day goes by without an article, podcast, or both highlighting the accelerating decline in global fertility. As I explain in my essay on the fertility wars, this discussion tends to divide interlocutors into two increasingly polarized factions. On one side are those who believe falling fertility is a grave problem; on the other are those who remain more sanguine, viewing declining birth rates as a natural consequence of modernity—or perhaps postmodernism—and less of a threat to economic growth, government budgets, or humanity’s survival. If women choose to have fewer children and prioritize careers and personal freedom—long the exclusive domain of men—shouldn’t we support that choice?

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The Fertility Wars (Audio essay)

Some people like to read, some people like to listen, some people prefer to write, while some speak. I am a bit of a mix, and if you are too, it’s possible that you’d prefer to listen to some of the writing on Alpha Sources rather reading it on a screen. Up until recently, that wasn’t really possible unless I either painstakingly, and poorly, recorded myself reading the text, or I paid an artist to do it for me, the latter which is a touch overkill given that I am not charging for access to my blog. Fortunately, AI voiceover technology is getting good, and fast, so good in fact that I am not able to introduce something new entirely; the Alpha Sources audio essay. These essays are powered by ElevenLabs, where I have recently become a subscriber. It’s fascinating what this tool can do, and I have only scratched the service, I am sure. I am kicking off with an audio version of my recent long-form essay, The Fertility Wars. All references and links used in this essay can be found by following the links above. The written essay contains two footnotes, which have been omitted in the audio version.

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Things to think about #4

The Economist’s Free Exchange column drops in on the question of an economic motherhood penalty from childbirth. It is nice to see that the Economist correctly distinguishes between two distinct economic motherhood penalties, both of which can be traced to the interplay between evolutionary forces and modernity, where the latter in this case is defined as an environment with rapidly increasing returns to investment in human capital and education. The first, between fathers and mothers, emerge because the cost of child-rearing especially in the early part of a child’s life overwhelmingly falls on the mother, a conclusion which follows from Trivers (1972). This is true in terms of the cost during pregnancy and immediately after too. It is also true before we consider the possibility that the resource allocation trade-off for many women shifts in the wake of motherhood. The second motherhood penalty occurs between women. Put simply, in an economic structure where childless women have the ability to devote all their resources to somatic investment and take advantage of the above-mentioned increasing returns to human capital investment, the wage and wealth divergence between women who have many children and those who have none will widen significantly, at least in theory. For more on this, I cover the theory in more detail in my essay on fertility and sexual selection; see here.

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