A Simple Model of Fertility Decline: The Marginal REVOLUTION
My core model is both simple and eye-opening. Fertility rates worldwide have declined due to the widespread adoption of birth control methods, which have become more effective and accessible. This shift in behavior, particularly among women, has led to a significant change in family planning preferences.
The history of birth control is indeed a long-standing process. While birth control pills became widely available in wealthier countries during the 1960s or 1970s, the diffusion of these technologies can be slow, and cultural norms take time to adapt. Additionally, the concept of 'fertility contagion' (https://x.com/MoreBirths/status/2020611577700143550) can take generations to fully impact societal trends.
Despite the long-term nature of these changes, social science provides numerous examples of similar slow-operating mechanisms (https://chatgpt.com/share/6989d758-3c74-8010-924f-66d55773864a). For instance, it took potential migrants a significant amount of time to exploit open borders before WWI. Moreover, fertility rates have been steadily declining in wealthier countries for a considerable period.
As a result, many women, once they experience the challenges of stress and financial strain, often opt for having only one child. This leads to a diverse family structure, including a large number of one-child families, some individuals who choose not to marry or have children, and a modest percentage of families with 2-4 children. Additionally, there are numerous cases where men leave, self-destruct, or never marry after having a single child with a woman, further contributing to the observed fertility rates, albeit with cultural and economic variations.
Richard Hanania (https://www.richardhanania.com/p/the-fertility-problem-is-getting?utmsource=post-email-title&publicationid=98102&postid=182414570&utmcampaign=email-post-title&isFreemail=true&r=3o9&triedRedirect=true&utm_medium=email) explores why income is not the sole driver of the decline and why the trend continues.
One aspect of this model is that many women genuinely love having children. They find such joy in parenthood that a single child can fulfill their needs and desires. I can personally relate to this; while I adore having Spinoza (my dog) around, I have no desire to bring another canine into my life. When I crave more 'dog attention,' I can assure you that the supply is highly elastic. Similarly, a single child can occupy a significant portion of your time and affection, and the supply is elastic from the child's perspective. Perhaps parents' evolving understanding of the joys of a single child has been another cultural lag?
Under this preference-driven model, reversing fertility declines is an arduous task. I believe this aligns with the evidence we have so far. This is a pressing issue that demands our attention, as the future implications are concerning. The asymptote suggests a decline in human well-being, potentially reduced innovation, and the possibility of significant fiscal crises. As Arnold Kling would say, 'Have a nice day.'
