The heritability of fertility makes world population stabilization unlikely
sciencedirect.com
sciencedirect.com
Yet my grandmother only had 4 children and my father only 2, and now I only have 1.
This is an anecdote, but I don't think heritabiliy has anything to do with it.
Large families simply happen due to poverty. When poor, you want more children because there's strength in numbers. Plus the women are staying home and can afford to have children.
Nowadays access to contraceptives is common and in Europe for example it's not feasible to have a lot of children due to costs (property, education, women having to eventually quit their job, etc).
Anyway, I think the evolution of poverty is a much greater predictor of population growth than anything else.
In a culture where large families were normal, perhaps genetic traits that push you towards having a large family were hidden by cultural aspects that made you have a large family. Only in an environment where having a large family is not the norm, will they surface and have an effect.
Just speculating here.
Poverty and risk, fertility changes lag behind medical advances / availability e.g. in europe the large families were mostly around the first half of the 20th century (to soon after WWII), where culturally you wanted to have a fair number of children so you'd have some living to adult age (and also manpower on the farm) but medicine had also progressed and spread enough that almost all of them would survive to adult age.
Culture quickly caught up and the default assumption that all children will live to adult age means even farming families aren't really large anymore (not to mention machines & automation makes the manpower of many children less relevant).
Developed countries are mostly at the point where medical advances are getting available, leading to huge families because the cultural aspect hasn't caught up yet.
Then you change the environment so that the trait is under strong selection. The people living in Scandinavia 3,000 years ago couldn’t digest lactose. Now ethnic Scandinavians who are lactose intolerant are basically nonexistent. It’s at above 99% homozygotes.
Imagine taking a population and killing everyone over 18 under 1.8m and doing this for four generations. Assuming anyone was left after the first generation the fourth generation will be substantially taller than the first.
Desire for children was never under strong selection pressure before because desire to have sex led to children pretty reliably up until the birth of the demographic transition in France in the ~1700s. Now it is under selection pressure, everywhere with reliable access to contraception so the people who like children are going to have more children, and their share of the population will grow.
> Large families simply happen due to poverty. When poor, you want more children because there's strength in numbers. Plus the women are staying home and can afford to have children.
This will be news to the Mormons, Amish, Hutterites and the Hasidim among a number of Orthodox sects of Jews. Large families do not just happen due to poverty. Some people want more children and arrange their lives around that.
Meanin 99% of people who have this allele (trait) have two set of the corresponding gene/genes.
Okay, but is lactose tolerance a dominant allele?
[0]: https://watermark.silverchair.com/151663.pdf?token=AQECAHi20...
You're right, they happen due to culture. However, the cultures you listed are notably insular and traditional, meaning they do not have large families for the same reason much of the world does (high infant mortality). I doubt these will ever change, but it is very possible the rest of the world will.
Also, ought we really to be brainwashing people to live how we wish them to?
It is not necessary that entertainment is so great.it is more that routine and isolation can be quite big.
TV is compatible with kids. But most social activities are nowdays are not.
Before birth control was available, there is not need for evolutionary effects in the willingness to have children directly, only for the willingness to have sex. You probably agree with me that sexual desire is pretty common, obviously we have evolved for it.
After birth control exist, sexual desire is not an appropriate proxy for evolutionary pressures, so, we could see an increase in the instinct to have children and, maybe, a decrease in the instinct of having a lot of sex.
Traits that will be selected: a desire to have more kids, physiological changes that cause resistance against contraceptives, tendency to have twins, etc.
https://www.newscientist.com/article/dn7147-genes-contribute...
http://blogs.discovermagazine.com/gnxp/2006/11/heritability-...
The replacement fertility rate to maintain population before modern medicine could be closer to ten than two not so long ago.
War, famine, disease, accidents, and infant mortality made it so surviving until you were old enough to start having your own children was rare and women were often pregnant or nursing continuously as long as they were fertile.
The premise of heritable fertility driving population and reproduction rates in humans is really far off. We're not having litters of kittens.
If it were true fertility rates could not possibly have dropped so far in so few generations after modern medicine and the insane reduction in violent death rates seen in the last thousand years.
Yes, until reliably accessible contraception fertility was driven by the desire to have sex.
> If it were true fertility rates could not possibly have dropped so far in so few generations after modern medicine and the insane reduction in violent death rates seen in the last thousand years.
This assumes no change in the environment, when it has manifestly changed. In this new environment in which desire to have children leads to having more children, on average, the desire to have more children will be selected for.
In urban societies, children are expensive to rear and educate until they can become productive, and the care of the aged depends on social institutions. This encourages small families.
However, if urban societies socialize the cost of rearing and educating children, then that disincentive will be removed and families may become larger. Ethnic subgroups with strong extended families and religious solidarity tend to have larger families, even in urban settings.
> In countries that have undergone the demographic transition, twin, adoption and family studies have pointed to a substantial genetic effect on fertility (Fisher, 1930; Kirk et al., 2001; Kohler, Rodgers, & Christensen, 1999; Murphy, 1999; Murphy & Knudsen, 2002; Rodgers, Hughes, et al., 2001a; Rodgers, Kohler, et al., 2001b). For example, Fisher (Fisher, 1930) found that a woman could expect 0.21 additional children for each additional child that her mother had, and 0.11 additional children for each additional child that her grandmother had. From this, Fisher suggested that the heritability of fertility at that time was 0.4 (40% of the variation in fertility is explained by genetic factors). Summarising research conducted through to 1999, Murphy (Murphy, 1999) noted that the heritability of fertility averaged around 0.2 in post-demographic transition societies, with the estimates increasing in recent periods. Kohler et al. (Kohler et al., 1999) examined data on Danish twins born in the periods 1870 to 1910 and 1953 to 1964. The first period covers the demographic transition and the second the end of the baby boom. In the first cohort, the heritability of fertility in women varied from close to zero in the pre-transition period to as high as 0.4 to 0.5 during the demographic transition. Estimates of heritability remained strong for the 1953 to 1964 cohort. From an analysis of data for Danish twins from the 1950s, Rodgers et al. (Rodgers, Kohler, et al., 2001b), attributed slightly more than one quarter of the variation in fertility to genetic factors. Rodgers and Doubty (Rodgers & Doughty, 2000) found a median heritability of 0.33 in a contemporary United States population, and heritabilities for underlying desires, ideals and expectations ranging between 0.24 and 0.76. Where measured, the variance attributable to shared environment in low-fertility populations was generally lower than the genetic effects (Kirk et al., 2001; Kohler et al., 1999; Kohler, Rodgers, Miller, Skytthe, & Christensen, 2006; Zietsch, Kuja-Halkola, Walum, & Verweij, 2014). However, the relative balance of genetic and shared environmental factors can change quickly over time (Kohler et al., 1999; Kohler et al., 2006).
Why shouldn't what worked for Europe work for the rest of the world?
The population behaviour of the British and that of descendants of those resident in Britain in 1900 are not the same thing. Focusing on nations obscures that fact.
ETA: I see from your other comment that you meant "stopped growing" so my comment doesn't really apply.
If you think about it, contraceptives are extremely similar to an antibiotic whose target is human beings. We're still living in the short-term when the antibiotic seems to be effective.
FRANCE: "We show a convergence towards French standards that differs across groups of origin. Women of Southeast Asian descent deviate from the fertility pattern of their parents, while those of Turkish descent preserve their parents’ cultural heritage. These different paths of adaptation between groups partly reflect cultural distance between parents’ country and host country. They also depend on family social capital, family structure, and family values. Access to a higher level of education is a crucial factor in erasing differences between groups" https://hal.archives-ouvertes.fr/hal-02081758/document
Not all religions have the same effect on the outcomes, ignoring that in the studies is misleading.
I guess it shouldn't be hard to conceive where Islamic parties start having a major voice in elections because of demographics.
Overall religion is secondary at best, but economically weak tribal/familiy social nucleus cultures vs established nation states that provide reliable social safety not just for relatives.
"It's the Economy, stupid", look at fertility rates of Saudi Arabi, Iran, UAE Poland vs Nigeria.
And what was found is that females from south-east Asia had a big drop in fertility whereas Turks continued to have large families, comparatively.
So, no, the above research specifically disproves your argument.
Not quite to the extent of some white European populations, sure, but very far from the "breeding like rabbits" image that politicians use to drum up fear among uninformed voters.
> the "breeding like rabbits" image that politicians use to drum up fear among uninformed voters
The fertility rates of muslim immigrants are far higher than the natives which will lead to a decisive demographic and political shift, which is what those politicians are talking about.
So if first generation migrants have a greater fertility, it can indeed affect demographics to a large degree. Because you need exactly one generation to do so. Obviously.
And it should also be obvious that lower fertility stems from multiple factors. Birth control is one, modern work structure is the other. I am certain there are more.
Then the environment changes in one, or in two ways. People move to another country, or not, and their culture gets exposed to modernity/the demographic transition. If they move to another country the culture they’re surrounded by will change, which will change when their children think it’s appropriate to marry, how many children they want, etc. It will do nothing to their genes, including their desire to have children.
But all over the world the selection is ongoing. As time goes on the proportion of the population that wants lots of children increases and so do the number of large families.
Genetic and sociological explanations can both be true at the same time. Mormons have more children than average for sociological reasons. They value and honour child rearing and family life far, far more than normal Americans. People whose parents had 6+ children also have more children than average, possibly partly due to role model effects, but mostly because they like children. There’s nothing incompatible about these explanations.
Isnt it obviously true? If you don't breed you don't pass on your non breeding genes, if you do breed....
Living organisms are literally breeding machines, that's all they really do. Natural selection favours those who do it better.
And, going one further, in the past people had children as a matter of rote. Now, it has to be a deliberate, overcoming the obstacle of modernity, in a sense. In the same way smallpox had a habit of reducing the population's potential, so too (by a different mechanism) does education, birth control, abortion, etc. A subset of the population will effectively become immune to those things.
When they refer to education reducing potential, they mean higher education levels generally correspond with a lower birth rate, for a variety of reasons. So smart parents having smart children does seem to fit with that.
Or am I misunderstanding what you're getting at?
Hope that helps to clarify.
Both fertility and intelligence are not as simple as the color of someones eyes. Lots of genes play a role, so the combination of two favorable gene-sets does not necessarily lead to a still favorable gene-set. Therefore, there always seems to be a "regression toward the mean", so don't worry, one or two generations cancel out all "preexisting conditions". Therefore, in every practical sense, both the heritability of intelligence as well as the heritability of fertility are negligible compared to other factors.
Of course children of more intelligent parents tend to get a better education, for example, i.e. those children can develop more of their potential, but here we're back to environmental parameters. But hey, this is good news, because it also works the other way around - dumb parents can have smart kids! So even if dumb people breed like rabbits, we just gotta make sure schools are properly funded to educate those children properly so they can develop their potential!
Anyway, I often hear that claim of 50-80% but I can never find the publications backing up that claim. Can you list some, please?
“First Law: All human behavioural traits are heritable.
Second Law: The effect of being raised in the same family is smaller than the effect of the genes.
Third Law: A substantial portion of the variation in complex human behavioural traits is not accounted for by the effects of genes or families.”
Beyond that though, the genetics of human fertility is pretty well understood. Here's a (now fairly old: from 2016) GWAS study on human reproductive behaviour: https://www.ncbi.nlm.nih.gov/pubmed/27798627
They show genetic correlations between reproductive traits and other behavioural traits in Figure 3. You might find it helps you develop an intuitive understanding. Happy to answer questions if you have any.
Isn't "intuition" basically the opposite of "science"? Shouldn't we try to answer questions about the latter, not the former?
[1]http://humancond.org/_media/papers/bouchard04_genetic_influe...
Genetic Influence on Human Psychological Traits
There is now a large body of evidence that supports the conclusion that individual differences in most, if not all, reliably measured psychological traits, normal and abnormal, are substantively influenced by genetic factors. This fact has important implications for research and theory building in psychology, as evidence of genetic influence unleashes a cascade of questions regarding the sources of variance in such traits. A brief list of those questions is provided, and representative findings regarding genetic and environmental influences are presented for the domains of personality, intelligence, psycho- logical interests, psychiatric illnesses, and social attitudes. These findings are consistent with those reported for the traits of other species and for many human physical traits, suggesting that they may represent a general biological phenomenon.
I wonder, shouldn't this be already observable? I would look not at the median/mean fertility, but on the outliers on the upper end. If the share increases/becomes more expressed in social groups that are not associated with a large number of children otherwise, one should see indicators that the theory is has some thruth.
Also, we are talking about heritability and entire generations. If such trend can be identified, I would expect it to be very small and take time (measured in generations) until it will have a real effect.
Then this study more directly measured fertility's rate of evolution: https://www.pnas.org/content/115/1/151. They used UK Biobank data (genetic data from 157,807 female and 115,902 male unrelated samples). They found the 'Age at First Birth' is the most strongly selected trait in the British population. So in the future we can look forward to a world filled with teenage mums.
That this is not obvious to everyone is just a testiment to how little people understand about evolution.
Exactly because things are not obvious, they need to be explained. As long as you do not explain the things you call obvious, you cannot judge if people do not understand a topic.
According to Hans Rosling's findings family size is linked to child mortality which is linked to poverty. When mothers see their children die then they want to have more children. When they see their children grow to adulthood then they have fewer children. You can also play with the data yourself on his site https://www.gapminder.org/.
He also looked at family size relation to culture and religion and found even in religions that promote large families, family size is still declining.
Family size has dropped world wide everywhere except for Africa. There is an unfortunate link between poverty and family size in Africa. The Bill and Melinda Gates foundation is tracking this exact issue.
I am not a data scientist, but the heritability of large families seems a difficult thing to pull out of the data when environment plays such a large role. In my personal family history child mortality and religion did play a large role in family size. We all now have small families.
His life work was reducing child mortality (under the age of 5.) He discovered that the biggest factor in reducing child mortality was the education level of the mother. It turns out that most child deaths are preventable if the mother understands how to prevent the death. For instance, dehydration due to diarrhea and vomiting can be prevented by sanitation. Also access to vaccines is linked to the education of the mother.
It goes without saying that access to birth control also plays a big factor. Melinda Gates tells a story about how she was talking to a group of African women about vaccines and what they really wanted was birth control so they could plan their family. They couldn't use condoms because culturally it implied they had AIDs. This also seems linked to education.
Actually, that was the conclusion, and is exactly the thing that is being disputed.
Anyway, the point is still: if someone makes a claim, they should be able to back that up. That is not done in the paper, and also I cannot find a post by you explaining the reasoning for your hypothesis.
Until there was a severe drought, when that type of beak was able to take advantage of a neglected source of foods, which wasn´t accessible to the other Finches - who were more sucessful, but only when there was abundant easy food. After the resultant die-off this particular Finch subtype dominated of course.
A lot of the discussion of evolutionary traits implicitly assumes an adaption to an unchanging environment, but that is very unlikely to be the actual situation, especially as in adapting, the adaption itself can change the larger environment.
My father's parents had 8 surviving children.
My mother's parents had 8 surviving children.
My parents had 4 surviving children.
I have 4 children.
My siblings have, on average, 3 children, and will probably have 3.5 over time.
My cousin's have on average 3.5 children.
Grandparents: Asian.
Parents: Asian and lived in Middle East half their life.
Me and siblings: Living primarily in Middle East.
We know that improvements in living conditions lead to reduced fertility. And climate change will worsen living conditions, not improve them. So if areas with poor living conditions have high fertility now, why would even worse conditions (due to climate change) reduce their fertility? Sure, the outcomes and quality of life of the children will be even worse than it is but I can't see how that will impact rates of reproduction.
Culture can change fast in either way, towards more children or less.
This does not mean we will be stable but rather culture matters.
For example soon as a member leaves a conservative religion stream and shifts to a more liberal streams their fertility instantly drops in one generation. Israel's government even models this in their demographics projects as the flow between religious streams of Judaism is the biggest fertility modifier in that country.
This does means in part conservatives will inherit the earth because liberal culture right now cause smaller families but this is culture. I think liberals have to fix this.
Also if a women gets an education her fertility drops and the more education the lower the fertility. This means uneducated women (for whatever reason, religious or other) will inherit the earth. If educated women tend to be those with more genetic talents, and in aggregate this may be the case, then this is quite a problematic trend long term.
I think the trends to who has fertility and who doesn't isn't great and should be a real topic of conversation. As a society currently we do not deal with this head on.
So is there any reason to believe that last "if" is true? Why would that be a problem anyway, as we can simply make sure schools are in good shape to educate those children, no matter the education level of their parents?
Many couples today reproduce with the assistance of reproductive technology. This releases selection pressure, so low-fertility genes proliferate.
>> This finding implies that individuals with genetic predispositions for an earlier AFB had a reproductive advantage and that natural selection operated not only in historical, but also in contemporary populations. The observed postponement in the AFB across the past century in Europe contrasts with these findings, suggesting an evolutionary override by environmental effects and underscoring that evolutionary predictions in modern human societies are not straight forward. <<
Yeah, so basically we got a simple model by two economists vs. decades of empirical data?
It'd be funny if it wouldn't sound like a scientists version of the "immigrants will have a lot of children and replace us" lie.
https://www.amazon.com/s?k=Who+We+Are+and+How+We+Got+Here&re...
If science does care about the JOURNAL impact factors too much, why then, as a consequence, would everyone publish in low impact factor journals?
-Journal is completely obscure to the genomics community
-No causal genetic mechanism is shown, everything is shoved into a "heritability" black box that some people seem to think is like your video game character starting stats or something
-Authors don't have a genetics background
-It's not my field, but there appears to be a wealth of literature on how fertility rates decrease in history, none of them involving "heritability" and little is done to address, reconcile or unify that
-There does seem to be darker political overtones that are exacerbated by commenters, leading me to think the arguments are not being made in good faith
Journal IF is just a (flawed) heuristic but in this case it sets a low prior and the "updates" didn't help
Are we reading the same comments section? Which specific comments are you talking about? The comments section I read seemed quite apolitical, except for this particular sub-thread.
>Low-IF journals are easier to publish to by definition.
It might be true that Low-IF journals in general are easier to publish to, but that's not true "by definition". By definition, Low-IF journals are journals whose papers are less-cited (this is an oversimplification, of course). For example, IF tends to vary a lot by field, so in your comment where you casually dismissed anything with IF<4 as a joke, you inadvertently dismissed whole entire fields. For example, one of the absolute top math journals, the "Annals of Mathematics", has an IF of 3.027. I can assure you, it's much harder to publish in the Annals of Mathematics than in a typical genetics journal with an IF of >=4.
> Are we reading the same comments section? Which specific comments are you talking about? The comments section I read seemed quite apolitical, except for this particular sub-thread.
Please.
>> Low-IF journals are easier to publish to by definition.
> (...) By definition, Low-IF journals are journals whose papers are less-cited (this is an oversimplification, of course). For example, IF tends to vary a lot by field, so in your comment where you casually dismissed anything with IF<4 as a joke, you inadvertently dismissed whole entire fields. (...)
Accepted. So in this specific case, do we talk about a journal in a field where an IF of 4 is low or high?
No, you please. I'm genuinely trying to reach a better understanding of your side. What comment did you think was the most political, outside of this sub-thread? Was it the one by car12 [1] which pointed out a quantitative observation about Muslim fertility rates and imagined a future where Islamic parties gain a bigger voice in politics through demographics? If so, what is it about that that's so political? Or if not that, then can you point to another comment that you think was particularly political?
This is also a good one:
> If an antibiotic doesn't wipe out its target, then its target's numbers will be devastated in the short-term, but in the long-term, its target will evolve immunity to the antibiotic and ultimately recover.
> If you think about it, contraceptives are extremely similar to an antibiotic whose target is human beings. We're still living in the short-term when the antibiotic seems to be effective.
Without any further detail or reasoning, just by "thinking about it" (whatever the author meant by that, he did not elaborate), the author draws a pretty extreme conclusion. This seems to be a rather unscientific, political attempt to reply to the original question:
> If this is true, then how do they explain population stabilization in, e.g., Europe, and other developed areas? Why shouldn't what worked for Europe work for the rest of the world?
Just because there's a political party committed to believing "the sky is red" doesn't make it political to say "the sky is blue".
I was the author of the "contraceptives are like antibiotics" comment btw. The point wasn't to make any extreme conclusion (I admit I can see how it could be taken that way in e.g. an abortion debate, but only by reading words between the lines that simply are not there). The point of that comment was not to score points in any political debate but to suggest an intuitive way to think about the results of the paper. Some commenters make the error of extrapolating straight lines, essentially saying "We observe reverse-correlation between education and birthrates over several decades, therefore they must be reverse-correlated forever". I pointed out an example, in a similar context[1], where such linear thinking would be wrong ("We observe the bacteria numbers are declining, therefore they must continue declining forever").
[1] Similar in the sense that they both involve living populations, population growth and decline, growth and decline caused by particular changes, etc.
Just to clarify this. Why is the former political and the latter not? Because one is false, and one is true?
I would argue that something is scientific or political no matter if its true or false. What counts is the way you try to convince others that it is true. Just as an example:
> The point of that comment was not to score points in any political debate but to suggest an intuitive way to think about the results of the paper. Some commenters make the error of extrapolating straight lines, essentially saying "We observe reverse-correlation between education and birthrates over several decades, therefore they must be reverse-correlated forever". I pointed out an example, in a similar context[1], where such linear thinking would be wrong
Here, you do not really explain why the intuitive thinking used by other authors (extrapolation) is less valid than the intuitive thinking you suggest: you do not explain why the comparison between humans and bacteria in the area of reproduction is valid, given the huge differences between humans and bacteria.
So when you say that "I admit I can see how it could be taken that way in e.g. an abortion debate, but only by reading words between the lines that simply are not there", that is kind of true: it is about the words that are not there - the words you have to provide to explain why your theory might not be wrong.
In that example, I'd say neither one is political. Now, if the one side started saying "Blue-skyers should be deplatformed", THAT would be political.
>Here, you do not really explain why the intuitive thinking used by other authors (extrapolation) is less valid than the intuitive thinking you suggest
I suppose if you really want to get down to brass tacks, my "contraceptives are like bacteria" comment was an instance of paradeigma, a rhetorical procedure popularized by Aristotle in which one attempts to help guide one's audience by presenting analogous anecdotes.
The difference between that and the extrapolators is that the extrapolators, at least in most cases I think, are unaware that they are falling prey to an unjustified extrapolation. None of them have come out and explicitly defended the implicit logic "Inverse correlation for the past several decades => inverse correlation forever". If someone DID want to explicitly defend it, they might use paradeigma right back at me, saying something like, "The inverse correlation is like the sunrise. We've observed the sunrise for a long time, and the sun will certainly continue to rise". Of course, such a rhetorical maneuvre would be unlikely to win many debate points, because the audience isn't stupid and can clearly see that analogy's too much of a stretch!
>it is about the words that are not there
But then basically you can twist anything at all into being political. I could say "1+1=2" and you could say "That's political! You're trying to imply something about binary genders, since you didn't explicitly throw out a disclaimer that you aren't trying to imply something about binary genders!"
Not that I'm trying to accuse you of consciously doing that... I think I'm guilty, myself, of sometimes reading politics into things that are apolitical. It can be particularly tempting to subconsciously categorize threads into teams, like, "This guy is X party and is on my side", "This guy is Y party and is the enemy". I've been trying recently to stop doing that, because I believe if I can get past that, there's a lot to learn from the people I thought of as enemies.
> Just because there's a political party committed to believing "the sky is red" doesn't make it political to say "the sky is blue".
Now you say:
> In that example, I'd say neither one is political.
That seems to be a contradiction.
> The difference between that and the extrapolators is that the extrapolators, at least in most cases I think, are unaware that they are falling prey to an unjustified extrapolation.
Yes, and I pointed out that also you do not give an explanation of why your proposed comparison is justified or not. (I do not think we need to involve the term "paradeigma" here, we can just use "comparison")
>> it is about the words that are not there
> But then basically you can twist anything at all into being political.
I don't really see the relation between my and your statement. Very generally: putting out statements without explaining the underlying thinking/reasoning/data at least exposes you to the accusation of being political, or unscientific, sure. Giving more detail, being more transparent about your thinking, explaining underlying concepts/data makes it easier for others to follow your reasoning, but exposes you to someone pointing out a mistake in your thinking. But well, that is science.
> I could say "1+1=2" and you could say "That's political! You're trying to imply something about binary genders, since you didn't explicitly throw out a disclaimer that you aren't trying to imply something about binary genders!"
I do not think that "1 + 1 = 2" falls in the same category as "the reproductive behavior of humans and bacteria are comparable". Therefore, in the example you gave, the answer is actually the political statement, as it brings in the completely unrelated topic of "gender" that no one was talking about and that has nothing to do with anything, just to try to win an unwinnable argument.
Perhaps I over stated the case by saying inevitable. It's quite feasible that the consequences of highly fertile people overbreeding will be a reduction in civilizational complexity, which will lowerthe total population.
> If you accept the heritability for age at first birth has not been measured wrong, then the hypothesis put forth by this paper will come about.
First you argue that if the paper is right, the measurements must be right. Then you argue that if the measurements are right, the paper must be right. Both arguments seem illogical, especially when used in that combination.
Please don't regurgitate common talking points about academia issues if you're just trying to score points in support of a fringe political position, that's not at all the direction we (as scientists that are critical of academia) want to go.
The filtering you refer to may be useful[1] when looking at bulk lists of papers (e.g. when sitting on a hiring committee), but this is an example where the article has already been curated for our attention, namely: by being upvoted on Hacker News. You can still choose to filter it out, but it's silly to write comments attacking the paper based on the journal's impact factor. Better to grapple with the paper's actual scientific content.
[1] (Useful in the same tragedy-of-the-commons way that it's "useful" to leave a picnic ground without cleaning up after yourself.)
On HN curation: while I certainly look up to this community when it comes to coding, technology and latest new software tools in general, I'm sorry to say the standards are not even remotely up to par when it comes to genomics. I assume it's because neither the mod team nor the majority of the community has a relevant background, and it's perfectly understandable. It does mean however that I, more often than not, encounter some pretty egregious stuff on here, especially when some dreaded words like "evolution" or "heritability" get mentioned. I sometimes try to chime in (and keep in mind I'm no authority beyond being a rando who happens to work in the field and knows plenty of people more qualified than me) but sometimes the disconnect between HN discussions and actual scientific community discussions is unreal.
On the paper itself: I didn't only mention its IF and voiced other concerns further in the thread. Ultimately there's a limited amount of time one may allocate to reading papers when there are literally millions of the damn things.
The idea here is to exchange information thoughtfully and to treat others kindly even when they are ignorant or wrong. If you know more, share some of what you know in a way that the rest of us can learn from. Don't post comments to put others down or bash their views.
We don't have these rules for ethical reasons or because we think it's good to be wrong. It's just that we want this place to stay interesting, and when internet users flame each other, that destroys the forum and causes smart people to leave. We want to avoid that scorched-earth outcome.