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[hector13]

I had a deep-fried chocolate bar from a chippy once.

It was massively underwhelming.

Deep-fried haggis isn't too bad. Bit too greasy though.

Deep-fried half pizza was a staple lunchtime meal for many at my high-school, though not something I ever tried.

[Avarice]

Yeah thats the dollar store fried bar equivalent; I've only had the same type but out there is some person who does just that and they have nailed it.
Cocoa in the flour, perhaps their fat is a perfect ratio of duck and pig lard bubbling at a browning temperature and they only use the new belgian chocolate mars bars or something.
A tiny ratio of chilli in the cinnamon sugar coating. Just enough to say "hmmm what is that" then the hell hound that was following you spews out the silver key and slinks back to its dark hole.
Just go back through the last hallway you passed through and open the locked door the +2 flail of incapacitation should be in there... If it's not its because you didn't pay the bridge troll an odd amount of gold coins. Its ok though you'll just get it after the boss

[EnigmaticHat]

Additionally, there's evidence that the mother's body can regulate the gender of babies. e.g. if you have more resources, male babies are more likely, and with less resources, female babies are more likely. The interpretation for this is that if you have high-resources, a male can grow strong and sire many children with different mothers, but if you have low-resources, then your more likely to get grandchildren from a girl. e.g. weak boys don't get as many dates.

That last bit seems hardly proven or even implied to me.  Alphas and betas have never been real, even in wolves.  And that's too much of an agrarian view.  In a pre-agriculture society, you share resources within your tribe and at a given time the nearby tribes will likely be going through the same feasts or famines as you since you both live off the land.  Its not about outcompeting nearby humans, its about weathering the bad times.  The version of this theory that I've heard was from a study that focused on modern times. It pointed out that the timing of the changes tended to be about 3 months after stressful events, implying that it wasn't about more males being conceived in good times.  Rather, its due to more male fetuses being miscarried in bad times.

It seems far more likely to me that having more girls in times of hardship is evolutionary insurance.  Without modern medicine, pregnancies are dangerous, and they become extremely dangerous for both the child and the mother if she is hungry or stressed.  In a bad situation, having sons doesn't help because yes they could get other people's daughters pregnant, but those daughters are probably malnourished and stressed as well.  So what you'd get is excess men because the women would die off far faster than the men.

Also the whole "one man, 300 kids" thing would never happen pre-agriculture.  Because resources don't get concentrated like that.  If one dude got 10 women pregnant, it wouldn't help spread his genes because the only children that survived would be the ones he helps raise.  In hunter-gatherer societies, human males pass on their genes through multiple females by sleeping around and having another male unwittingly raise their kid.

[ChairmanPoo]

Additionally, there's evidence that the mother's body can regulate the gender of babies. e.g. if you have more resources, male babies are more likely, and with less resources, female babies are more likely

I would like to see a citation for this. Gender is determined by the chromosome payload of the spermatozoid, and for the most part the mother does not really play much of a role in it. Unless I'm misssing anything.

Pd:
https://en.wikipedia.org/wiki/Human_sex_ratio

Lots of mentions to environmental factors, but no mention of adaptative factors that I can see. 

[Reelya]

No, there's recent evidence that's it's not actually completely random.

[ChairmanPoo]

Do you have any links? Because allI've found is thatit's close to 1:1  and that environmental factors are minor and... pretty random, really

[Reelya]

Well a quick google brings up this:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0023792

Evolutionary theory posits that resource availability and parental investment ability could signal offspring sex selection, in order to maximize reproductive returns. Non-human studies have provided evidence for this phenomenon, and maternal condition around the time of conception has been identified as most important factor that influence offspring sex selection. However, studies on humans have reported inconsistent results, mostly due to use of disparate measures as indicators of maternal condition. In the present study, the cross-cultural differences in human natal sex ratio were analyzed with respect to indirect measures of condition namely, life expectancy and mortality rate. Multiple regression modeling suggested that mortality rates have distinct predictive power independent of cross-cultural differences in fertility, wealth and latitude that were earlier shown to predict sex ratio at birth. These findings suggest that sex ratio variation in humans may relate to differences in parental and environmental conditions.

Trivers and Willard predicted that, in polygynous mating systems, mothers in good condition could increase reproductive success by biasing investment in sons. Superior quality sons can leave many more offspring than daughters can. Hence, where the fitness gains of offspring quality are sex specific, a female with ability to produce high-quality offspring could be expected to produce more sons and vice-versa. Empirical evidence for biased offspring sex ratios gathered from many taxa support this theory
...
Meta-analysis of non-human studies has suggested that sex ratio adjustments are most likely to occur around the time of conception. This adjustment was strongly correlated with maternal condition around conception, such that mothers in good condition during this period produced more sons. Similar findings have been reported in humans when maternal condition was considered in relation to sex ratio adjustment

Average national sex ratio at birth (SRB) in humans is slightly male biased (105 males per 100 males), with remarkable deviation for some countries. Systematic deviations from this ratio occurs in conditions such as economic and natural catastrophes, war, chronic stress, etc. Demographic factors like ethnicity, parental age, mother's weight, birth-order, smoking, certain disease conditions, certain professions, exposure to environmental toxins, seasonality of birth, etc are also linked to sex ratio adjustments. These studies have shown that higher birth-order, older parental age, low or high maternal weight, exposure to toxins and stressful events lower the chances of male births

So basically, things seen as "unhealthy" e.g. the mother being old or too fat or too thin, or malnourished or stressed or sick from toxins, all reduce the chance of a male birth. The interesting part here is that all the observed "negative" things about the mother's condition seem to reduce the chance of having a boy: not one of them increases the chance.

The possibility that the human natal sex ratio may relate to variation of life-expectancy and mortality rates has received surprisingly little attention from researchers. Indeed, only one study has investigated the relation between life-expectancy and natal sex ratio in a small sample of contemporary British women, finding that women who believed they had longer to live were more likely to have a male birth than women who thought they would live shorter

I'll make the suggestion that this field of research has had "surprisingly little attention" from researchers because it's not politically correct to suggest that people would have more male children if you improve their standard of living, regardless of how scientifically accurate it is. We have no issue however observing gender variation in animals, so this has in fact been observed in dozens of other species.

However this also opens up some interesting perspectives on deliberate sex selection in impoverished nations. If the theory is correct, then impoverished people have more girls, but the problem is that we enforce monogamy, not polygyny, which is what innate sex-selection is geared for. Hence, impoverished nations would have excess girls by that measure, and would need some boy-baby bias just to maintain equal sex ratios. However, when standards of living then rise, that cultural sex-selectivity is now out of whack with the sex ratios, leading to excess male births.

That's exactly what we see in India and China - excess male population is blamed on generations of sex-selectivity. However, India and China didn't have a "girl shortage" until very recently, but the practices of pro-male sex-selection go back centuries. The data on poverty and innate gender selection can explain this issue.

EDIT: Note that the nation with the most skewed birth ratio in favor of boys is Lichtenstein, with 1.26 boys born per 1.0 girls. Some people are claiming that Lichtenstein people are seriously aborting the "missing" girls. However ... abortions aren't even legal in Lichtenstein, and it's hard to believe that literally 1 in 5 baby girls are aborted in the entire nation in the world's richest nation per capita, when you'd have to either do a backyard abortion or travel to another nation to get it done, and yet nobody is noticing this happening. Note that Lichtenstein has the highest GDP per capita of any nation in the world, along with an extreme level of income equality, so it might be an outlier of what happens when you have a large group of people who all have good nutrition and standard of living etc. A very low ratio of female births.

[EnigmaticHat]

...you don't need an abortion to achieve that effect dude.

Edit: Specifically referring to China and India, I honestly hadn't heard of Lichtenstein until right now.

[Reelya]

My point was that people are making assumptions about demographic changes here that could be explained by non "murdering your firstborn" means. Since we're basically neglecting an entire potential subfield of relevant research here, then we can't in fact assume anything about why it's happening (or alternatively the scale of things), without proper evidence.

In fact, it's probably explainable by racism that we automatically assume it's because evildoers when it's another race, but when it's our own race we go "well who's to say why it's happening?".

e.g. an extremely wealthy nation such as Lichtenstein is a great barometer here, since it's highly unlikely they're bashing girls to death at birth or secretly aborting 20% of fetuses, when they don't even have abortion clinics there. And their birth ratio is far more skewed than China!

And this does in fact call into doubt our dominant narratives about why China's birth ratios are so skewed. Like I said, they could have originally had a skew to girls, because of biology and centuries of poverty - hell, they had the sex-selection thing going for 2000 years and never had a "girl shortage" before. But now that incomes are rising, the sex ratios (biological speaking) have stabilized, yet culture still has the "baby boy bias" that used to be adaptive, but is now maladaptive. Unfortunately, since sex ratio at birth is in fact reactive to maternal health, it's not possible to quantify the amount that this is happening, just from the birth records, as many sources are trying to do. So the reported estimates of infanticide are probably over-estimates since they're not taking into account that rising nutrition means more baby boys, biologically.

[Mathel]

While I would believe that "girl" fetuses have higher survival rate than "boy" fetuses when the mother is not healthy, I do not get how that would skewer the demographic in the other direction in the other direction when the mother is healthy.

As gender is given by which chromosome is in the spermatozoid, there would have to be a different factor, which would make Y chromosome spermatozoids have a higher chance to reach the ovum in order to actually ever make male babies more likely.

[Yoink]

My pants broke just as I was leaving the house to participate in social engagements. I stuck on a button badge I had lying around, it held them (more-or-less) up until I made it to the supermarket (which was fortunately only a small detour on my way to the station) and bought a pack of "nappy pins" (just big safety pins, decorated in calming pastel colours) to replace the lost button.

Then, noticing with dismay that the next train was apparently half an hour away, I ensconced myself in a gross train station toilet stall to perform these makeshift repairs. I stuck a pink pin in first (because it basically jumped into my hand when I opened the pack), followed by a blue one for added security, then I spent the next few minutes trying to figure out if I'd dropped a pin on the floor without realising, as I could have sworn the packet contained four pins, yet I had only one pink one left.

Then the train showed up unexpectedly - apparently one had just been running late, and the thirty-minute wait was a lie. It's a good thing I'm not too deaf to hear trains from inside a public toilet.

Can't remember if there were more wtfs I planned to mention - oh! My outfit feels extremely nineties this evening. Also things have been smelling weird these past couple of days, but that's a story for another post.

[Reelya]

While I would believe that "girl" fetuses have higher survival rate than "boy" fetuses when the mother is not healthy, I do not get how that would skewer the demographic in the other direction in the other direction when the mother is healthy.

As gender is given by which chromosome is in the spermatozoid, there would have to be a different factor, which would make Y chromosome spermatozoids have a higher chance to reach the ovum in order to actually ever make male babies more likely.

The actual data trumps what you believe.

I do not get how that would skewer the demographic

It really doesn't matter whether you "get it" to whether it's true or not. The data suggests it's true, the theorists predicted it, and it's found to be true in numerous taxa of animals. Plus it correlates with data from human populations. By Occam's Razor it makes sense to take as the starting point the assumption that it's a similar mechanism for a similar reason in the various species, unless we find a jolly good reason that humans would be the odd one out.

https://www.cnbc.com/2015/11/13/shiny-happy-people-means-more-boys-being-born.html

Happy people give birth to boys.

That sounds crazy, but there's a fair amount of evidence that positive or negative events can change the ratio of boys to girls being born.

Hosting the 2010 World Cup caused a boom in male babies in South Africa nine months afterward, according to a recent paper by researchers in Johannesburg. Conversely, the death of Princess Diana or the 9/11 terror attacks were shown to reduce the percentage of males compared to total births — the so-called M/F ratio.

Economics can also shift the ratio. Declines in male babies have been correlated with higher unemployment rates, and according to another recent paper, the ratio plummeted going into the Great Recession — suggesting that the M/F ratio functions as a lagging indicator of economic well-being.

https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-10-269

Women in job types that were categorized as "high stress" were more likely to give birth to daughters, whereas women in job types that were categorized as "low stress" had equal sex ratios or a slight male bias in offspring.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158943

Changes in Income at Macro Level Predict Sex Ratio at Birth in OECD Countries

The human sex ratio at birth (SRB) is approximately 107 boys for every 100 girls. SRB was rising until the World War II and has been declining slightly after the 1950s in several industrial countries. Recent studies have shown that SRB varies according to exposure to disasters and socioeconomic conditions. However, it remains unknown whether changes in SRB can be explained by observable macro-level socioeconomic variables across multiple years and countries. Here we show that changes in disposable income at the macro level positively predict SRB in OECD countries. A one standard deviation increase in the change of disposable income is associated with an increase of 1.03 male births per 1000 female births. The relationship is possibly nonlinear and driven by extreme changes. The association varies from country to country being particular strong in Estonia. This is the first evidence to show that economic and social conditions are connected to SRB across countries at the macro level.

So regardless of the specifics, there are a whole bunch of research avenues and they're all hinting at the generally the same thing, which is that the birth ratio is responsive to macro-level life events. And if the birth ratio can be manipulated, then it makes sense that evolution would try and manipulate that for adaptive purposes.

We can start to make predictions however once we have a few data points and see how well those line up with actual studies, e.g. single women should be more likely to have a baby girl than a married woman. Because the stress of working a job is more stressful on the body that being supported. Sure enough, digging into some old research, that's exactly what they found:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691865/

In a sample of 86 436 human births pooled from five US population-based surveys, I found 51.5% male births reported by respondents who were living with a spouse or partner before the child's conception or birth, and 49.9% male births reported by respondents who were not

[Mathel]

No Reelya, it does matter to whether or not I will believe you.

You claim, that the fact that female fetuses have higher resistance to bad conditions makes male fetuses thrive better than them in good conditions.

I do not say, that I do not believe you, that males are born more often in good conditions. I only say that females being more resistant is not enough to cause that.

[Reelya]

You claim, that the fact that female fetuses have higher resistance to bad conditions makes male fetuses thrive better than them in good conditions.

Did i? If we're going to debate then you can start by citing things I said, not making shit up.

All I did was to cite the correlational data that sex at birth is highly reactive to macro-level information, and that the effects are in line with adaptive theories. In fact, I never made a single reference to "fetuses" at all. So you're kind of arguing with yourself there.

In fact, the idea that male fetuses merely die more easily and thus explains the whole thing isn't quite born out by the statistics. More males in total are born than females, however the gender split at conception is effectively 50:50. Here are two recent independent pieces of research making that claim:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4413335/
https://www.ncbi.nlm.nih.gov/pubmed/25825766

So somehow the system "knows" to favor boy embryos in "good" conditions and girl embryos in "bad" conditions. It's not merely that male embryos are more fragile.

I've always been talking about this as a holistic thing. e.g. you have the proximate reason things are true due to this stimuli or that stimuli, but then you have the reason it was like that in the first place - which is natural selection determined that this was the optimal way for things to be structured. Clearly some things are not influenced by natural selection but they tend to be things that are unimportant for procreation. And "sex ratio at birth" is clearly something that's deeply important for procreation. So to the extent that genes can influence the connection between relevant environmental factors and sex ratios at birth, you'd expect them to be strongly regulated.

[Mathel]

Well, you may or may not have said anything about fetuses. You could have edited it away as well.

My point was that people are making assumptions about demographic changes here that could be explained by non "murdering your firstborn" means. Since we're basically neglecting an entire potential subfield of relevant research here, then we can't in fact assume anything about why it's happening (or alternatively the scale of things), without proper evidence.

In fact, it's probably explainable by racism that we automatically assume it's because evildoers when it's another race, but when it's our own race we go "well who's to say why it's happening?".

e.g. an extremely wealthy nation such as Lichtenstein is a great barometer here, since it's highly unlikely they're bashing girls to death at birth or secretly aborting 20% of fetuses, when they don't even have abortion clinics there. And their birth ratio is far more skewed than China!

Wait, there it is.

Well a quick google brings up this:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0023792

Evolutionary theory posits that resource availability and parental investment ability could signal offspring sex selection, in order to maximize reproductive returns. Non-human studies have provided evidence for this phenomenon, and maternal condition around the time of conception has been identified as most important factor that influence offspring sex selection. However, studies on humans have reported inconsistent results, mostly due to use of disparate measures as indicators of maternal condition. In the present study, the cross-cultural differences in human natal sex ratio were analyzed with respect to indirect measures of condition namely, life expectancy and mortality rate. Multiple regression modeling suggested that mortality rates have distinct predictive power independent of cross-cultural differences in fertility, wealth and latitude that were earlier shown to predict sex ratio at birth. These findings suggest that sex ratio variation in humans may relate to differences in parental and environmental conditions.

Trivers and Willard predicted that, in polygynous mating systems, mothers in good condition could increase reproductive success by biasing investment in sons. Superior quality sons can leave many more offspring than daughters can. Hence, where the fitness gains of offspring quality are sex specific, a female with ability to produce high-quality offspring could be expected to produce more sons and vice-versa. Empirical evidence for biased offspring sex ratios gathered from many taxa support this theory
...
Meta-analysis of non-human studies has suggested that sex ratio adjustments are most likely to occur around the time of conception. This adjustment was strongly correlated with maternal condition around conception, such that mothers in good condition during this period produced more sons. Similar findings have been reported in humans when maternal condition was considered in relation to sex ratio adjustment

Average national sex ratio at birth (SRB) in humans is slightly male biased (105 males per 100 males), with remarkable deviation for some countries. Systematic deviations from this ratio occurs in conditions such as economic and natural catastrophes, war, chronic stress, etc. Demographic factors like ethnicity, parental age, mother's weight, birth-order, smoking, certain disease conditions, certain professions, exposure to environmental toxins, seasonality of birth, etc are also linked to sex ratio adjustments. These studies have shown that higher birth-order, older parental age, low or high maternal weight, exposure to toxins and stressful events lower the chances of male births

So basically, things seen as "unhealthy" e.g. the mother being old or too fat or too thin, or malnourished or stressed or sick from toxins, all reduce the chance of a male birth. The interesting part here is that all the observed "negative" things about the mother's condition seem to reduce the chance of having a boy: not one of them increases the chance.

The possibility that the human natal sex ratio may relate to variation of life-expectancy and mortality rates has received surprisingly little attention from researchers. Indeed, only one study has investigated the relation between life-expectancy and natal sex ratio in a small sample of contemporary British women, finding that women who believed they had longer to live were more likely to have a male birth than women who thought they would live shorter

I'll make the suggestion that this field of research has had "surprisingly little attention" from researchers because it's not politically correct to suggest that people would have more male children if you improve their standard of living, regardless of how scientifically accurate it is. We have no issue however observing gender variation in animals, so this has in fact been observed in dozens of other species.

However this also opens up some interesting perspectives on deliberate sex selection in impoverished nations. If the theory is correct, then impoverished people have more girls, but the problem is that we enforce monogamy, not polygyny, which is what innate sex-selection is geared for. Hence, impoverished nations would have excess girls by that measure, and would need some boy-baby bias just to maintain equal sex ratios. However, when standards of living then rise, that cultural sex-selectivity is now out of whack with the sex ratios, leading to excess male births.

That's exactly what we see in India and China - excess male population is blamed on generations of sex-selectivity. However, India and China didn't have a "girl shortage" until very recently, but the practices of pro-male sex-selection go back centuries. The data on poverty and innate gender selection can explain this issue.

EDIT: Note that the nation with the most skewed birth ratio in favor of boys is Lichtenstein, with 1.26 boys born per 1.0 girls. Some people are claiming that Lichtenstein people are seriously aborting the "missing" girls. However ... abortions aren't even legal in Lichtenstein, and it's hard to believe that literally 1 in 5 baby girls are aborted in the entire nation in the world's richest nation per capita, when you'd have to either do a backyard abortion or travel to another nation to get it done, and yet nobody is noticing this happening. Note that Lichtenstein has the highest GDP per capita of any nation in the world, along with an extreme level of income equality, so it might be an outlier of what happens when you have a large group of people who all have good nutrition and standard of living etc. A very low ratio of female births.

But it is nowhere near 20% actually.
Total amount of live born children in Lichteinstein in 2011 was 395. Lichtenstein is tiny.
In the same year the ration boys/girls was 1.26/1 That means that out of 2.26 children 1.26 were boys and 1 was girl.
1.26/2.26=0,558
1/2.26=0,442
Multiplied by the number of children born:
0.558*395=220
0.442*395=175

So, the difference between girls and boys was only 45 children.
If girls were added to have equal amount, total children would be 395+45=440
45/440=0,102
Only about 10% of fetuses would have to be aborted without a clinic. 20% of girl ones though.

Also in the same post you said that there does not seem to be anything increasing the chance of boy being born and that it is increased by something in Lichtenstein.

But The Principality of Lichtenstein is so small, that most of statistics there are not representative.