Gender Imbalance: Effects of Excess Females?

[Darmalus]

I was wondering if anyone knows of, well, anything about the results of having a significant gender imbalance among humans where there are significant excess females?

While I'm swimming in dire predictions of China and historical examples of excess men, I'm really not finding anything on the opposite. Has this simply never happened? Or just never studied?

[Broomstick]

I'd be curious about those historical examples of excess men.

Some primitive groups NEVER had an excess of women because they used female infanticide as birth control - there was one group that practiced polyandry in North America that, if an infant girl couldn't be promised to TWO males for future marriage she'd be killed. Very, very harsh environment they lived in, took two men to support one woman and her kids, hence the polyandry (well, I guess that's a historical example of excess men right there, isn't it?). Some islands in Polynesia practiced infanticide, either general or selective, to maintain populations that their island could support. Discontinued these days since excess population can simply move elsewhere these days, most of those islands have an agreement in place for some mainland nation or other to take on their excess, and much more reliable birth control. Really, I don't think anyone is enthused about killing babies, it's just that for some folks in history it was viewed as the least bad alternative or something.

Anyhow - I'd look for post-warfare groups. Used to be pretty common for the conquerors to slaughter all the adult men and take the women and children as slaves, which would lead to a gender imbalance, particularly if the invaders took significant casualties among their own men. Probably has contributed to polygyny in various cultures.

I think post WWII the Soviets had a gender imbalance in favor of women, which accounted for a lot more female professionals there than in the US during the Cold War, but I'm not clear on how extreme that was.

As a general rule having extra women isn't that disruptive, they're less inclined to rebel or start violent problems than excess young men are.

[Adam Reynolds]

If you believe their stories, the Mormons claim that this was the reason they instituted polygamy. Whether it was really this or really because the early church leaders made sure there was an excess supply of women is debatable(by making an effort to recruit young women, many of them widows). Though in any case only a minority actually had multiple wives, largely due to financial reasons.

I think post WWII the Soviets had a gender imbalance in favor of women, which accounted for a lot more female professionals there than in the US during the Cold War, but I'm not clear on how extreme that was.

I don't recall the exact figures, but there were easily millions more women than men by war's end. Notably, if you were a male born in 1923, you had a virtual guarantee of dying in the war(as you thus were 18 when Barbarosa began). I at some point read that the Soviets had a policy of encouraging young men to impregnate young women without marriage as it was a means to rebuild the population after the war. Though given the source*, I'm not entirely sure of it.

* It was from Dirty Little Secrets of WW2 by Dunnigan and Nofi, which I read as a teenager and later realized just how full of holes it was. Dunnigan's books all generally have this problem, while interesting reads, they are consistently full of minor inaccuracies that even I can easily see. They also all fail to cite sources at all, which is odd for the market that he writes for.

As a general rule having extra women isn't that disruptive, they're less inclined to rebel or start violent problems than excess young men are.

Steven Pinker made this point in The Better Angels of Our Nature, that it was generally better for a population to have excess females.

[madd0ct0r]

It's not like an excess woman has to take risks to attract a mate

[Broomstick]

No, but if the gender imbalance is great enough she might not find a mate.

That's not so bad in modern or relatively egalitarian societies where a single woman can support herself, but that would be disastrous in a society where there is not legitimate for her to make a living.

[Darmalus]

I'd be curious about those historical examples of excess men.

According to German scholar Gunnar Heinsohn, European imperial expansion after 1500 was the result of a male “youth bulge.” Japan’s imperial expansion after 1914 was the result of a similar male youth bulge. During the Cold War, it was male youth-bulge countries—Algeria, El Salvador, and Lebanon—that saw the worst civil wars and revolutions. Heinsohn has also linked the recent rise of Islamist extremism in countries like Afghanistan, Iraq, and Pakistan to an Islamic male youth bulge.[lxx]

Unfortunately the site flubbed their biblography and gave a wrong link. But wikipedia seems to agree with that summary.

As I dig more and refine my search terms to exclude China (who's utter dominance of the topic prompted this thread) I find more historical cases of excess women after various wars (US Civil War, WW1, WW2). This seems rather preliminary, but from the looks of it, when ever this happens it seems like the excess women would just buckle down, find a job and wait to die. That strikes me as real sad and I rather hope I'm wrong.

[Broomstick]

Remember that prior to the modern era bearing children was risky business for women, and that not all women want to marry men. Post-war imbalances favoring women might make it socially easier for such women to simply not bear children and not marry. Some of those women probably moved in with other family, friends, or neighbors - farms and homesteads could always use another hand for labor. They may not have been married, that doesn't mean theirs was a miserable existence.

Excesses of young men can result from either a die-off of women (this might even be due to such things as the normal rate of childbirth mortality in a society) or a lack of marriageable women if the society condones polygyny and the women are "snatched up" by older or wealthier men. Doesn't have to be even a majority of men having more than one wife, there must be some sort of tipping point where the percentage of polygynists tips the balance into a shortage of wives for younger, less wealthy men.

In the distant past, young men dying off due to either the risks inherent to making a living (both hunting and farming are dangerous occupations even today) or in defending territory/trying to acquire new territory probably resulted in a surplus of women more often than a surplus of men... except women tended to die earlier due to childbearing risks. Of course, there was also the "solution" of raiding your neighbors and simply stealing their women, which sort of sucked for both the men who were killed in such raids and any women who were carried off.

[Alyrium Denryle]

I was wondering if anyone knows of, well, anything about the results of having a significant gender imbalance among humans where there are significant excess females?

While I'm swimming in dire predictions of China and historical examples of excess men, I'm really not finding anything on the opposite. Has this simply never happened? Or just never studied?

In terms of population demography, no problem whatsoever unless population growth is a problem (read: unless you want to bring down population growth). A population with a female biased nominal sex ratio will usually have the same reproductive rate as a population with the same female population but an unbiased nominal sex ratio. This will be true until males can no longer mate with available females, which for mammals like humans is a very large number indeed. There are societies where being an unwed mother AND being part of a polygynous marriage is socially unacceptable and that makes reproduction difficult, and there you might see a drop in reproduction for a generation or so.

This is where we get into polygyny threshold models. Social polygyny in humans tends to occur for one of two reasons (This is in contrast to genetic polygyny and indeed genetic polyandry, both of which are ubiquitous irrespective of what is or is not socially acceptable). Patchy resources that can be monopolized by a territorial male, or a female biased nominal sex ratio. Alternatively, it may occur due to the historical occurrence of one or both of those two with the resulting polygyny being maintained culturally (which will lead to a male-biased operational sex ratio if the original conditions do not hold true, or were not the result of a female biased nominal sex ratio).

Basically what happens is that females will accept polygyny when the fitness benefit (measured in terms of parental investment in offspring) of being someone's second mate is greater than being another male's first mate. This is expandable to N mates.

Illustrative example: If a pastoral oligarch has a shit load of sheep, he can provide the resources needed to care for 2 wives and their offspring to a greater extent than the dude who has a much smaller herd of sheep. So a prospective second wife is better off in evolutionary terms selecting him to be her mate than she is selecting the poorer shepherd.

When the sex ratio is biased, this choice becomes even easier, because being someone's second mate is almost certainly better than going it alone.

We use this to model polygyny across bird species, but the same holds true for human cultures when you take the time it takes for cultures to adapt to changing conditions into account. You also get social factors (like Patriarchy in certain forms) that make the cultural system more resistant to change.

The factors that create a female biased sex ratio can be transitory (like the Nazis invading and killing the lions share of the men between the ages of 16 and 45), or persistent (such as the mortality rate of males from internecine warfare or Doing Stupid Things To Get Laid being higher than the rate at which women die in childbirth). Transitory changes tend not lead to cultural shifts that make polygyny socially acceptable in societies that are traditionally monogamous (or polygamous). Persistent ones will, given enough time.

[Darmalus]

Interesting. So society works fine as long as there is <=1 male per female (assuming population replacement), with the lower limit being around when the genetic bottleneck becomes an issue?

[Broomstick]

There are societies where being an unwed mother AND being part of a polygynous marriage is socially unacceptable and that makes reproduction difficult, and there you might see a drop in reproduction for a generation or so.

Serial monogamy might help with that, though. If a man has children with three different women he doesn't have to have them as mate simultaneously. Cultural tolerances and norms vary in how much that is tolerated (some societies allow divorce, some don't) and how easy it is to accomplish.

[Alyrium Denryle]

Interesting. So society works fine as long as there is <=1 male per female (assuming population replacement), with the lower limit being around when the genetic bottleneck becomes an issue?

Generally, yeah. If a population is male biased, there are problems. Male humans engage in a lot of Stupid Shit To Get Laid as it is with a relatively even sex ratio. Particularly when they young. Risk taking to impress females, violence to secure resources and social status among their peers to attract females, violence because they are frustrated at not having access to females...

In human cultures there are really only two ways of dealing with those problems. Male infanticide, or finding a way to expel males when they hit sexual maturity. Lost Boys in Utah are a good contemporary example of this, but historically wars would also be fought. Draft a bunch of teenagers into the army, give them a pike and send them to besiege your rival's fortress. Vikings are a good example too. They had a slightly male biased population and their land was kinda hard-scrabble, so competition for mates was higher (bride price goes up) so in order to marry Hilda who lives four houses down the lane, they had to go A Viking and raid an english monastery.

[Alyrium Denryle]

There are societies where being an unwed mother AND being part of a polygynous marriage is socially unacceptable and that makes reproduction difficult, and there you might see a drop in reproduction for a generation or so.

Serial monogamy might help with that, though. If a man has children with three different women he doesn't have to have them as mate simultaneously. Cultural tolerances and norms vary in how much that is tolerated (some societies allow divorce, some don't) and how easy it is to accomplish.

Roman society was pretty flexible that way, if I recall. I dont know what their sex ratios were like but given the number of men in and out of the army who were not allowed to marry until their 30s or 40s in many cases...

[Broomstick]

If I recall, historical records indicate that at least among the upper classes you typically had multiple sons in a family but only one daughter (in general - of course individual families varied). Where did the missing women go? Romans were known to practice infanticide (and picking up abandoned infants was also a source of slaves). Speculation was that upper classes limited the number of women they bothered to raise because of the cost of marrying off women, and the costs of raising a daughter would ultimately benefit the family she married into and not the family that raised her.

Not sure what the lower classes did, in large part because they weren't as well documented.

[Alyrium Denryle]

If I recall, historical records indicate that at least among the upper classes you typically had multiple sons in a family but only one daughter (in general - of course individual families varied). Where did the missing women go? Romans were known to practice infanticide (and picking up abandoned infants was also a source of slaves). Speculation was that upper classes limited the number of women they bothered to raise because of the cost of marrying off women, and the costs of raising a daughter would ultimately benefit the family she married into and not the family that raised her.

Not sure what the lower classes did, in large part because they weren't as well documented.

It would be a demographic impossibility to maintain their population with widespread female infanticide, given early childhood mortality rates, even with large numbers of children. They would go into top-down demographic collapse. I know they practiced infanticide, but just to maintain population replacement, roman women would have had to have six to nine children on average. Widespread selective infanticide of girls pushes that up even higher, leading to even higher female childbirth mortality.

To my knowledge, there is only one surviving document indicating female infanticide, and it is a personal letter from a soldier to his wife, but that is one case. One might as well flip a coin. Catches of bones from babies killed (presumably by their parents) are not sex biased. Presumably they used infanticide as a means of family-size planning.

[Broomstick]

A Roman woman with three or more children did enjoy a better status than one who had fewer, certainly they did encourage women to have kids.

Did the upper classes seek wives from lower social strata or not? That might have affected keeping daughters among the elite while still providing sufficient wives for their sons.

Truth is, it can be hard to find solid facts on past demographics.

[Alyrium Denryle]

A Roman woman with three or more children did enjoy a better status than one who had fewer, certainly they did encourage women to have kids.

While that is true, mortality on the birthing bed limits the number of children women can have without, you know, dying. At the point where population replacement requires more than 6 children on average, it is not a matter of encouragement, it is a matter of possibility. It just was not mathematically feasible. Especially when you consider that the romans breastfed for an extended period.

Plus there is precisely zero evidence that they engaged in female specific infanticide. None whatsoever, besides a single letter, and every bit of evidence to suspect that they used infanticide irrespective of the sex of the offspring.

[Broomstick]

What about the missing daughters? Again, it was my impression (which may be faulty due to poor information) that upper class Roman families tended to have significantly fewer daughters than sons. A lack of older women could be attributed to childbirth fatalities, but wasn't there a sex imbalance prior to that point? How would that be accounted for?

[Alyrium Denryle]

What about the missing daughters? Again, it was my impression (which may be faulty due to poor information) that upper class Roman families tended to have significantly fewer daughters than sons. A lack of older women could be attributed to childbirth fatalities, but wasn't there a sex imbalance prior to that point? How would that be accounted for?

I would need reference material for the lack of women, but if we are talking about literary or civic records and the like, it was a misogynistic culture. Women tend to be under-represented in records, or the way in which they are recorded is idiosyncratic. For example, mercenaries enfranchising their families in Miletus (Greek but it illustrates the concept) might only register their co-resident female children when they reach child bearing age, because that is the age at which women at that become socially and legally relevant, and when they marry, they are no longer in your household.

[Simon_Jester]

No, but if the gender imbalance is great enough she might not find a mate.

That's not so bad in modern or relatively egalitarian societies where a single woman can support herself, but that would be disastrous in a society where there is not legitimate for her to make a living.

Although in a society where this is a widespread phenomenon and there are thousands upon thousands of 'surplus' women, it is almost inevitable that society will adjust to accept women living alone and supporting themselves.

Most societies adapt to the social circumstances they find themselves in, rather than riding a counterproductive cultural trait into the ground. Although there are exceptions to that rule.

[Darmalus]

No, but if the gender imbalance is great enough she might not find a mate.

That's not so bad in modern or relatively egalitarian societies where a single woman can support herself, but that would be disastrous in a society where there is not legitimate for her to make a living.

Although in a society where this is a widespread phenomenon and there are thousands upon thousands of 'surplus' women, it is almost inevitable that society will adjust to accept women living alone and supporting themselves.

Most societies adapt to the social circumstances they find themselves in, rather than riding a counterproductive cultural trait into the ground. Although there are exceptions to that rule.

This is apparently what happened in Britain, since they seemed to have a significant surplus of women for at least a century from around 1850 onward. Probably due to constant attrition from war.
https://en.wikipedia.org/wiki/Surplus_women

The only apparent social consequences was allowing unmarried women to work and improved factory conditions, not wanting thousands of women starving in the streets or damaging their future reproductive chances with factory work.

[Simon_Jester]

Britain's military casualties usually weren't that high in any given year prior to World War One; it'd tend to average out. It may not have been so much all the Britons who were dying overseas, as those who were living overseas. If the population of your country is biologically more or less normal, but 5% of the male population gets on a ship and goes to the colonies to help administer or garrison them, while essentially none of the women go... you end up with a country that has the kind of sex imbalance observed here.