Heritability of Pronatalism: Can We Evolve Our Way Out of Demographic Collapse?

In this deep dive episode, we explore Jacob Hornstein's controversial article that suggests JD Vance and Elon Musk misunderstand the genetics behind falling birth rates. Our hosts examine the evidence from Fisher's 1930s research on fertility heritability to contemporary studies across the US, Britain, Denmark, and Sweden, assessing the role of genetic predispositions in fertility rates. They discuss the rapidly evolving environmental pressures impacting reproductive strategies, the socio-economic factors at play, and the implications for future demographics. The hosts also share personal insights into how cultural and personal contexts shape fertility behavior, offering a nuanced perspective on genetic determinism vs. environmental influence. This episode aims to provide a balanced understanding of the genetics of fertility in the context of modern societal changes.

Simone Collins: [00:00:00] Hello everybody. I'm so excited to be speaking with you today because I came across a, an article in the Hill by Wunderkin Jacob Hornstein, who's actually in the class of 2028 at UATX, the new Renegade University. And he made this really key argument that I think is underrated in the world of prenatalism.

He, the title of the article, JD Vance, Elon Musk are right about falling birth rates. But here's where they get it all wrong. What do you think is his point? Well,

Malcolm Collins: you've told me about this already. He thinks it's genetics and that it will be washed out and he's just super wrong and not good at math. But continue, Simone.

Simone Collins: I think it's an important conversation to be had because it is, he makes some valid points and he points to some valid information But he is missing some very important details. So he starts the article with their efforts are notable, but fans and Musk both underappreciate the role of genetics in determining fertility without a proper understanding their efforts were fail will fail.

Now I think both [00:01:00] fans and Musk are really up to date on genetics.

First he points to the research of Ronald Fisher and this is where I learned something new because I didn't realize that this concept that fertility is heritable.

goes back to as early of the 1930s. So in 1930, this guy named Ronald Fisher wrote a book called The Genetical Theory of Natural Selection. And I love genetical as a word. Can we bring that

back? Yes.

In which he talks about the correlation between genetics and fertility

from the article, Jacob writes, Fisher noted that the granddaughters of large families tended to have more children than those from small families. Fisher concluded that, quote, about 40 percent of the total variance, end quote, in fertility was attributable to genetics. He continues, Importantly, Fisher didn't just conclude that fertility varied between individuals because of different genetic abilities to have children.

Instead, Fisher argued that the most important cause of variation was different genetic desire to have [00:02:00] children. Fisher theorized that more fertile strains with a greater desire for children could become more common within a span of 10 generations or approximately 250 years. So immediately, this is where The argument both is legitimate but incredibly flawed and you see where the flaw is, right?

Malcolm Collins: Well, no, the flaw is not where you think it is. Okay. You think the flaw is, let me see if I'm getting you right here, you think the flaw is around timelines for impact.

Simone Collins: Sort of.

Malcolm Collins: What do you think the flaw is?

Simone Collins: Well, we don't have 250 years to bounce back from the vertiginous drop

Malcolm Collins: in fertility. That's not sort of, I was exactly right.

Simone Collins: Oh, I thought you meant like, that it was going to take a long time.

Malcolm Collins: Here's what it gets wrong. It literally doesn't understand evolution at the most base level.

Simone Collins: Okay.

All right, let's see if I can condense the point I tried to make while talking but ended up being very long.

Pointing out that [00:03:00] fertility is heritable in humans, or that people who have higher rates of fertility end up having kids who have more kids, is not the same as pointing out something like blue eyes are heritable, and people with blue eyes end up having more kids, because fertility is a near direct correlate or marker for fitness within modern human populations, where people aren't dying of diseases, , or from lack of food.

Now the very fact that we're seeing Significant genetic variation and fertility related behaviors within a population isn't evidence that one variant is strictly quote unquote better in evolutionary terms. If it were consistently advantageous across environments, it would have been optimized through selection.

Instead, this variation signals that the environmental pressures are changing, creating different selection conditions that temporarily favor certain genetic predispositions before changing again as society evolves. E. g. the very fact that in this [00:04:00] initial study he found that some women had these genetic Precursors to predilections for having lots of kids and other women didn't have that meant that there must not have been this strong selective pressure that he was observing in his own time if you went back ,, 250 years before his own time or that one behavior pattern would have already been selected for.

So, an example, we can look at here is, if you look at the distant past. And food was scarce and there wasn't modern medicine, there would have been an evolutionary benefit

for a woman not being overly impulsive in who she was sleeping with, and ending up having too many kids. Whereas there would have been pretty much a strict evolutionary benefit during a period where, you know, , you have modern medicine and modern food. To this level of impulsivity, , that might lead to tons of kids.

But then this benefit may disappear [00:05:00] when contraception comes onto the scene. , and evolutionary strategies that relied on impulsivity suddenly stop working. So you can see as the environment changes, the psychological.

Correlates to high fertility also change, and right now we're dealing in a time where the evolutionary environment is completely doing somersaults every few years, if not at least every couple decades.

Malcolm Collins: I mean, Evolution has been acting throughout this entire period. It didn't start in the 1930s, right? And so what he's noticing here is in the 1930s, certain genetic predilections or, or I'd say certain personality predilections that had genetic correlates led to a higher fertility rate then, then they would have in the past and are now being strongly selected for but here's the problem with all of that, the personality profile or predilections that [00:06:00] differentially led to a high fertility rate in the 1930s versus, let's say, just 100 years before that are radically different than the ones that lead to a high number of children today.

Simone Collins: That's a really good point. I hadn't even thought about that because we live in such a different landscape with so many different pressures. Right. And if it was conformist and cool to have kids back then, then you're the last person to have kids now.

Malcolm Collins: Exactly. As, as we've pointed out, actually society was in this generation.

And this is the primary thing I would argue that's leading to fertility collapse. Because if you look in Latin America, you look at the United States, it's mostly. Women under 24 who are not ha