They not only traditionally dispose of most females for believing males are more valuable workers/warriors, but also of any offspring which doesn't look the right way after the first couple of months (if it doesn't have the right eye and skin color combination).

The people started as a normal civilization, was diminished by tribal and world wars and became purists/racists after the Great Humiliation, their last attempt of taking over the whole Continent. This forced them into a retreat deep into their traditional territory. Their numbers were down to about 10 000. No exact numbers are known because their Capital was destroyed during the Great Humiliation.

The Leaders blamed the defeat on the lack of purity of The People, who had, in earlier times, mixed with the others, so they forced the Pure Ideal on the rest of the population.

The People are ruled by a "Holy Oligarchy". The leaders call themselves Descendants/Heirs of the Powers (even if most of them know this is a lie and don't even believe the Powers exist) and take advantage of this to do whatever is best for themselves.

They do keep some females for reproduction, this makes females precious possessions and trading "coin". The ones with the right skin and eye color combination that most resemble their ideal of "purity" are the ones kept for the Leaders, the others are used as best serves their society.

Some, if they are a bit off, but are the firstborns of a mother, are kept to serve as slaves and possible reproducers, or to be given as rewards to the most loyal males. These females however will not even be allowed to see their newborn children, as lower casts are technically not allowed to reproduce.

Every male child is always allowed to live, as long as after about 8 weeks they show no over-obvious signs of having the wrong colour of eyes and skin. For instance, they might live if they have brown eyes instead of the desired black, or be freckly instead of having a clear overall colour. They might be a bit off the ideal and still be accepted in society but will never be allowed to breed.

A female who happens to be the firstborn of a mother is allowed to live, unless after the 8 weeks limit they present two unwanted traits. They may have freckles if their eyes are black, or have brown eyes if their skin is uniform. But if they happen to have both freckles and brown eyes, then they'll be "taken care of".

After that, from each and all newborn only the most "perfect" females are allowed to live.

The burden of perfection falls on the females, not the males.

How long could such a society survive before it crashed?

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    $\begingroup$ Do they dispose of every female? if so then they wouldn't last very long at all. $\endgroup$
    – F1Krazy
    Sep 20, 2017 at 14:20
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    $\begingroup$ About 100 years if they get rid of all females immediately, even if every member of the population died of old age. Probably around 150 years if they only get rid of newborn females and use the ones they already have as "baby producers" until they go through menopause and can't produce any more. $\endgroup$ Sep 20, 2017 at 14:23
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    $\begingroup$ How can a single "race" species be racist (unless they pull an US)? So it is implied that there are more "races"? Can/do they mix with each other? Are you sure you want an entire race behave like that or do you mean (I'm sorry, I know you've stated otherwise, but I've seen everything so far) something like a small nation-type construct that can kidnap/rape/recruit "people" from the outside world? $\endgroup$
    – Raditz_35
    Sep 20, 2017 at 14:24
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    $\begingroup$ What you have done is to increase the amount of children dying. As for survival of the tribe that does not do much as long as people keep breeding and keeping up the birth rates. HOWEVER... how long do you think people will put up with this before they go "Stop killing our babies you morons! There is nothing wrong with them!!". As for "disposing of females", as everyone else pointed out: males do not get pregnant... bye bye tribe in — literally — a man's age. $\endgroup$
    – MichaelK
    Sep 20, 2017 at 14:36
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    $\begingroup$ "They dispose of females"... "keep some for reproduction": Killing females is the surest way to go extinct. While a nation can easily survive the loss of 50% of its males of reproductive age (the French did it twice, the Germans did it three times), losing a large percentage of the females would be deleterious. For the potential consequences in a real-world situation you may want to look up the missing girls of China (although at closer look it appears that most were not missing, just hidden). $\endgroup$
    – AlexP
    Sep 20, 2017 at 16:01

9 Answers 9


First we'll have to suppress our instinctive cultural reaction against eugenics; the concept has some bad connotations on Earth, and has always gone poorly.

I'm assuming that your people are basically humans.

These guys can survive with a scheme like you describe, though it comes at a high cost:

  • Population -- since most females are killed -- yikes! -- the size of the next generation will be artificially limited. The elders will have to prepare for a rapidly shrinking population; the extent of this problem is proportional to how stringent their requirements are (hair/eye color you'd mentioned), and how rare such combinations are in the base population. They become more susceptible to disease or foreign intrusion.

  • Misery for females -- in order to have any hope of keeping their numbers up, the surviving women will have to have children. Lots of children. Making this happen can lead to a level of social control over women that modern folks are uncomfortable with.

  • Anger for parents -- it's tough to get people to agree to this. They will hide nonconforming babies, dye their hair, invent colored contacts, etc. Especially if the criteria for "wrong" babies are purely cosmetic. They will resent this setup deeply, again more so depending on the percent of culled children.

  • Misery for males -- in a low-female environment, males will be unhappy and resentful. Competition to court women will be intense. Promises of betrothal will become currency. Expect a lot of crime, a lot of anomie.

  • Lots of killed children -- this part is going to be difficult. Difficult for parents to give up their children. Difficult to find someone willing to do the job.

  • Lots of "unright" children -- if the gene pool is made too narrow, there will be many unfortunate reinforced recessives. Many birth defects.

What you're really describing is an artificial population bottleneck and a forced founder effect. Eventually, if some more laid-back tribe doesn't intervene, the "right" look will be spread out enough through the population that this eugenics program will no longer be necessary. But Lord, the cost.

The elders of this tribe ought to think long and hard before engaging in a program like this. Most especially if they decide to implement it as a law or policy; the change will seem cruel and arbitrary, and may be resisted furiously. It would take Bene Gesserit-like levels of social engineering to make this idea "spontaneously" arise, which I don't really see happening.

They might get more sustainable results if they try the "carrot" approach. Reward "the look", tax breaks, etc. If the elders don't like women, split the society into moieties -- guys and gals -- which only come together at predefined times. There are options, fellas.

Edit: Forgot to mention this; there is a book, "In Conquest Born" by C.S. Friedman which had a tribe which tried a similar scheme. They got "the look" they wanted, but it caused them endless problems. Check it out!

  • $\begingroup$ Yes, that's where this particular race is going. They are driven by hunger for power, even among the lower classes. After a time females became a bargaining product. They are NOT a happy intelligent productive people. $\endgroup$ Sep 20, 2017 at 19:42
  • $\begingroup$ They might not be happy, but they are intelligent enough to do it right without any advanced tech. $\endgroup$
    – Or4ng3h4t
    Oct 24, 2023 at 9:42

First off, no race (species) or sub-race (ethnicity), will last very long if they dispose of all their females. Just to maintain zero-growth in a civilisation where females & males are at 1:1, each female will have to produce two children. One to replace herself and one to replace her male counterpart.

As your culture aborts / abandons / otherwise "disposes of" its girls, the remaining females will have to work harder just to maintain population. Eventually, some war or other natural disaster will come along and utterly destroy this culture and that will be an end to the madness.

As for the other question, a race could very easily maintain itself and even expand its population while breeding out minor things like wrong eye or skin coloration. We do this (eugenics) with all kinds of domestic animals and plants. The principle is the same when applied to people. If you want to breed out a particular physical trait, you simply cull the herd. Those who are found to express a trait are simply removed from the breeding population. I leave it up to you to determine whether that's by killing them or sterilizing them or expelling them.


Disposing of your females is not a good way to maintain your line. Guys have a hard time making babies with each other, even if they try very hard. This aspect of their eugenics scheme betrays a stupidness which bodes poorly for this group.

For animals, clearly selective breeding can and does keep lineages pure - purebred dogs are an easy example and breeding is crucial for other lines of domestic animals. As you state, defective animals must be put down and so presumably the same would be true for humans.

Some eugenics prinicples are covered here How much crossbreeding should there be in a human eugenics program?

With brother sister matings (or father daughter) if you are lucky enough to emerge from an inbreeding crisis you can emerge with pure lines and no recessive genes.

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    $\begingroup$ Citation needed for 2nd sentence $\endgroup$ Oct 4, 2017 at 0:17

Maths is not on their side. I don't know how extreme your "they do keep some females for reproduction" is meant to be, but here are some quick and dirty calculations on how many kids each woman would have to bear to keep the population stable.

enter image description here (Again, I can't get the wretched image to load - if anyone can screengrab it and paste it in here, please do).

So say you want 1000 babies born every generation. You then immediately kill 50% of girls just for being girls, then kill 5% of girls and 10% of boys for 'defects' - when the surviving (225 of 500) girls grow up, each mother needs to have 4.44 kids to make those 1000 babies.

If you get rid of 75% of girls (for being girls plus 'defects') then each mother needs to have 8 kids. If you get rid of 85% of girls (for being girls plus 'defects') then each mother needs to have 13.33 kids. If you get rid of 95% of girls (for being girls plus 'defects') then each mother needs to have 40 kids!

The above figures assume NO infant mortality for either sex, NO death in childbirth, NO infertile women, and NO women dying due due to accident, disease, etc before they give birth to their final child. Obviously this is unrealistic, so the number of babies each woman must produce will be higher than the above numbers.

Here are the infant mortality rates for modern countries and for the world since 1960

Meanwhile, in some animal species, Inbreeding depression leads to reduced fertility, which will drop the birth rate. This may also apply to humans.

  • $\begingroup$ They keep females considered of "pure lineage" and with the right type, usually the first born to a new mother, and if she his lucky enough to look right after a few weeks. Hadn't considered normal infant mortality though... Thanks $\endgroup$ Sep 20, 2017 at 19:51
  • $\begingroup$ Also the birth rate is about double of that with each female giving birth to at least 8 kids in her lifetime. $\endgroup$ Sep 20, 2017 at 20:02
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    $\begingroup$ @shieldedtulip. Is that 8 kids total? Or eight kids AFTER the cull? Because statistically speaking, she'll have 4 boys and 4 girls. So if Mum is only allowed to keep her firstborn girl, and the other 7 must be boys, then she needs to give birth to up to 14 kids to get those 7 boys. She might get 'lucky' and have several boys in a row before she has a 2nd girl. $\endgroup$
    – DrBob
    Sep 22, 2017 at 9:00
  • $\begingroup$ that's at least 8 total, but I'm aiming for the "better" females to give birth to around 14 kids between ages 16 and 40. If they live long enough... plus, this society has good knowledge of herbs and herbal medicine. They are unintelligent but smart enough... if that makes sense. $\endgroup$ Sep 22, 2017 at 10:47
  • $\begingroup$ They are what can be called a pre-enlightenment close to medieval society. $\endgroup$ Sep 22, 2017 at 10:48

Females are more critical to a species' survival than males. If they kill a large percentage of them, that will be the impotus for their own extinction. If they have a very narrow definition of "race" (as you say here: skin color and eye color), they will also likely have to inbreed to stay "pure," which might sound cool and very Targaryen-eqsue, but madness is not the only side effect of inbreeding (see Tangier Disease and the many medical issues plaguing royal families of Europe due to inbreeding for more information). In essence, your race will likely be the cause of their own demise.

  • 1
    $\begingroup$ Inbreeding will not be a problem with the initial population of 10 000 people. Phenotype preference is thought to be the driving force in an observed dominance of lighter hair, skin, and eye colour in Europeans. So, there is no problem here as well. However, you are right that females are more important for species survival. $\endgroup$
    – Olga
    Oct 3, 2017 at 20:16

Persistent disposal of females: A much-needed workaround

As others noted, females are much more important for the survival of species using K-strategy for reproduction (few offspring, high parental investment in reproduction). Humans, normally, are K-selection species. But your setting introduces selection pressures that would greatly favour females that can produce more offspring at a lower cost.

So, in a rather short time (from an evolutionary standpoint), female anatomy and/or gestation will change to produce babies in a more effective way. Therefore, The People will move toward r-strategy (plentiful offspring with low investment). This is the only way for your species to have an evolutionarily stable strategy (ESS), if [this is a very important if] they continue to practice disposal of females in great numbers.

There are two things to consider:

  1. your females should be very fertile and childbirth should be quite safe to keep the population stable:

    • necessary fertility rates depend on number of women surviving the culling;
    • population growth would require even higher birth rates;
    • a number of children that can be born at the same time can be important (are twins, triplets, quadruplets, etc. common or not?);
    • safety of childbirth can be increased medically; if midwives are not available, there will be more pressure for faster anatomical changes.
  2. disposal of females must[see note] be culturally mandated once the desired traits are firmly established in population:

    • a culling system that you describe combined with sufficiently high fertility to avoid dramatic decrease in population will produce phenotypically homogenic population in just a few generations (it takes only about 10 generations to create new breeds of domesticated animals and plants with strict selective breeding; 10 generations is about 150-200 years for humans if women start to give birth around 15-18 years old);
    • unless the requirements of the Pure Ideal are constantly adjusted to become stricter the majority of baby girls will meet them, therefore, they will not need to be culled.

Note: according to the Fisher's principle, sexually reproducing species favour 1:1 sex ratio, without major evolutionary changes this will hold true for The People. However, considering that male offspring have higher chances of passing their genes, there is a possibility that over time the sex ratio will become skewed in favour of boys.

Survival of The People

If The People can keep a balance between culling and birth rates they can survive as long as they have enough resources to sustain their society. There is no problem with the population.

Inbreeding will not be an issue since you start with 10'000 people. However, the fewer women The People keep the more desirable it becomes to mate them with different men to produce genetically diverse offspring.

If you use just a few males as 'prize studs' to start a purebred population you may run into some genetic problems. However, your ruthless culling system will take care of serious physical defects. Moreover, since mating is quite heavily regulated, less obvious anomalies will be selected out later in life. In other words, I would not be concerned with genetics. The greatest challenge for The People would be achieving replacement fertility.

It would also make sense to keep breeding records similar to the ones used for purebred domesticated animals. Pedigree charts could be a nice cultural touch :)

Some things to think about

You should probably consider dividing your female population into 'breeders' and 'milk cows'. This will help to increase fertility rates and male offspring survival. Obviously, selective breeding should be used here as well. 'Breeders' would be valued for their perfect appearance, while 'milk cows' for docility and milk production. The latter can also be used to satisfy sexual desires of lower class men.

The People would also develop very distinct sexual patterns. I suspect that male homosexuality will become a norm, maybe something close to ancient Greece or pre-modern Japan. Some sort of a third gender (male sex, but different from male gender identities and behavioural patterns; gender is not the same as sex) is also very plausible. I believe in your setting that would be a true third gender rather than feminine men. It can provide some exciting possibilities for world-building and character development.

There are some theories that societies with male-dominated sex ratios are highly unstable and prone to violence, crime, riots, and so on. Especially, if they have a great number of young bachelors. I would suggest taking a look at research on China or South Korea sex ratios. If your society has too few women and does not have mechanisms to channel aggression and sexuality outside of community it may collapse just because of the riots and social unrest. A never-ending war can be a possible solution.

  • $\begingroup$ Somw good points, although I don't think a third sex is even remotely likely despite the fact that it would make for very interesting stories and worlds. $\endgroup$
    – Slarty
    Oct 6, 2017 at 15:42
  • $\begingroup$ @Slarty, third gender is not the same as third sex. There are plenty societies that have more than just two genders. $\endgroup$
    – Olga
    Oct 6, 2017 at 17:19
  • $\begingroup$ I had assumed gender equated to sex, but perhaps not... $\endgroup$
    – Slarty
    Oct 6, 2017 at 22:41
  • $\begingroup$ @Slarty, check this map for examples of cultures with more than two genders. $\endgroup$
    – Olga
    Oct 7, 2017 at 0:17
  • $\begingroup$ I had always considered gender to be synonymous with sex. And Judging by the first two paragraph of your link, its because most western societies have no direct correlation with other traditions. I suppose a lot of it boils down to semantics. I have always been well aware of the different shades of sexual preference across the two basic sexes and cases of people born with hybrid male/female genitals. But I had never heard "gender" used in such a way. I can see the logic and utility of it. I wonder how long it will take for this meaning of the word to spread in western culture? $\endgroup$
    – Slarty
    Oct 7, 2017 at 13:01

Forever, if you hand-wave why they are intelligent at all

Even better, that can be more or less natural behaviour for them, but they can't be anything like us, or any species we consider intelligent (in terms of animal intelligence). In fact, you would have to hand wave why species with that kind of reproductory strategy is intelligent at all, but lets start from the beginning.

You want species where reproduction doesn't put much strain on females. This rules out mammals, as mammals are species which invest a lot of energy (food, nutrients - chemical energy, as well as proverbial energy) into offspring, which limits fertility, but massively increasing chances of offspring having own offspring.

This also rules out birds and most reptiles, because while those hatch from eggs, most bird and reptilian species care of their newly hatched. Sure, either progenitor can care for newly hatched (social species could potentially have offspring taken care of by other members of society), but laid eggs are still not an insignificant investment.

What about fish and amphibians where egg laying and external fertilisation is common? There quantity over quality thrives. Fish and amphibians lay a lot of eggs, and have a lot of offspring, expecting most of them to die very young. One egg is negligible investment since they are produced in hundreds or thousands, and progenitors don't care about offspring in the slightest.

Here you have it, you can have amphibian species which, after somehow gaining sentience and technology, deliberately puts down most of their females and most of their offspring, yet still thrive, because their reproductive cycle is designed to plow through attrition with sheer numbers. If after gaining sentience they do care about worthy offspring, then in fact, described behaviour becomes necessary to prevent overuse of available resources to the point of endangering entire species.

The main problem is explaining how they got sentient in the first place. Complex brain takes a lot of resources to grow and operate (large fraction of your food goes to sustaining just your brain), and a lot of resources are needed to nurture offspring with such demanding organ. Benefits in terms of projected survival are huge, of course, even without going as far as humans did (quite a few mammals and birds use simple tools, and that already is a huge help in finding food) but energy requirements are a reason why this strategy is used by species which extensively care about newly born or newly hatched (in elephants mere gestation takes nearly 2 years, young ravens stay with parents for about half a year after learning flight). Newly hatched quantity-based amphibians won't be able to acquire enough food to develop brains, making evolution in that direction impossible - those which by mutation do have slightly more complex brains will actually be less likely to survive than their brethren.

Right now, I have no idea how to jump that hurdle, but if you do, you can have external-fertilisation amphibians behave and thrive exactly the way you described, if they do provide care for those offspring that is deemed worthy and consider killing females a very ruthless form of... contraception.

As I said, they are nothing like us, or any species we consider smart.

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    $\begingroup$ And I just realised that this puts neo-nazis appropriating Pepe the frog in entirely new light... $\endgroup$
    – M i ech
    Sep 20, 2017 at 16:19
  • $\begingroup$ My problem is not so much the species/race/kind but how long would they survive before collapse comes. $\endgroup$ Sep 20, 2017 at 19:44

There is no limit on how long this society can last

Societies normally die from other factors like revolt, invasion, government collapse, apocalyptic event, disease, etc.

The factors you posed do not directly affect the lifespan of such a society.

Some things you did mention could but their effect is variable based on their magnitude.

  • The amount of reproducible women, genetic diversity is critical for any civilization/colony if you reduce the pool to much inbreeding and terminal recessive traits become more prolific. Such would be equivalent to disease in its capacity to destroy society.

  • injustice and governmental control, The Romans and Americans got away with horrific treatment of its lower classes but were able to maintain control of them through military might and a methodical draconian punitive system. Slave revolts have historically come close to or even successfully managed to overthrow their oppressive societies.


Looking at Wikipedia's article on Dog breeds, modern controlled dog breeding started in Victorian era. Let's take the establishment of the English Kennel Club in 1873 as the starting point. That gives us approximately 150 years of controlled breeding, which resulted in the congenital health problems plaguing purebred pooches today.

The Wikipedia article on canine reproduction states that the larger breeds of dog reach sexual maturity at as old as two years, which would mean a human year is indeed seven dog years for our purposes. A smidgeon of menial multiplication results in 1050 years until The People inbreeds itself to destruction. I'm going to submit this as my answer since it hits amusingly close to the Thousand Year Reich promise of the Nazis.


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