I read a theory once which stated that the natural pain, sickness and general discomfort that humans can experience during sex, pregnancy, and childbirth help control the human population by discouraging uncontrolled breeding.

If this is true, here is the synopsis of my question.

I have been working on an alternate human species which experiences natural earlier sexual development, lacks a menstrual cycle and experiences little to no physical pain, sickness or discomfort from sex, pregnancy, and childbirth.

To expand upon these points:

These alternate humans can engage in safe and prolific breeding before the age of 10. They can have over 6 children in a single pregnancy with the largest recorded birth comprising of 11 children all who lived past infancy. The birth rate for these alternate humans is largely the same as real humans.

These humans are completely immune to any and all sexually transmitted diseases. They had no concept of STD's until they accidentally discovered them in animals.

These humans have malleable sexual organs. I think this would create an intended lack of sexual pain which may encourage higher rates of casual sex.

As mentioned, these humans have little to no pain, sickness or discomfort caused by pregnancy and childbirth. I'm not sure how exactly this would work on a biological level but pregnant women of this alternate human species retain their agility during all stages of pregnancy and can easily support the unborn baby weight. They also have a snake jaw like pelvis which contributes to the painless childbirths.

This alternate human species also has a stronger sex drive which manifests at a young age. In a nutshell, young individuals of this alternate human species are natural nymphomaniacs and may breed with individuals that they have a weak connection or relation too.

Lastly, this alternate human species lives in a culture that has fully embraced its sexuality. It doesn't attempt to regulate peoples sexual habits or preferences unless said habits or preferences invoke inherent, undisputed and auomatic harm onto another person.

Would an alternate human species with such attributes have a significantly greater population?

I expect that food and resources would still pose an eternal problem to this alternate human species. If these sexual attributes remove population inhibitors, I think that disease and resources would be the sole remaining natural inhibitors.

I can answer any questions that someone may have about this topic if it helps. I'm also open to any critiques given that they point out a flaw in this alternate human design that should or can be rectified to achieve the intended goal rather than simply questioning why I needed to write any of this.

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    $\begingroup$ Historically, without a major pestilence or political event, human populations tend to increase until the food runs out. Also, there is a huge set of differences between human hardwired sex drive (mostly hormonal and hindbrain), the local cultural attitudes (often suppressing sexual activity among the powerless and poor), and the resulting conscious choices of folks toward sex ("I'm sure I'm doing the right thing!"). The question seems to assume that conscious choice is perhaps more powerful than it really is. $\endgroup$
    – user535733
    Feb 18, 2020 at 3:24
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    $\begingroup$ I suspect no change. Other factors are far more significant. In Ireland, for example, the effects of the Great Famine was to reduce the population from 8 million in 1840 to about 6 million in 1860 and a consistent decline to about 4 million in 1980 - about 120 years of emigration driven by the cultural impact of one socioeconomic event ! Other countries have similar stories. The 100 years wars, Caesar boasted he killed one million Gauls, WW1 and WW2, Mao and Stalin's "social" reforms - the list is endless. Your culture would presumably still be affected by things like these. $\endgroup$ Feb 18, 2020 at 5:48
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    $\begingroup$ Do these alternate humans reach adulthood at a similarly early stage? That would probably be the defining factor. $\endgroup$
    – user72572
    Feb 18, 2020 at 7:22
  • $\begingroup$ @user-1387425094 These Alternate humans recognize adulthood as the age at which sexual development is completed, which for them is 13. They don't recognize mental, emotional or physical maturity as contributing factors of adulthood. $\endgroup$ Feb 18, 2020 at 14:05

2 Answers 2



At least, not significantly greater. The theory that the pain of childbirth is what stops humans from having children isn't that substantiated - while childbirth is painful, it's not why people don't want to have children. I suppose on a subconscious level, it might affect a small percentage, which is why I say that it wouldn't make humans significantly greater.

There are numerous reasons why humans do not have children, and they still come into play here. These reason include material reasons, that is the ability to care for and provide for children, and societal reasons, that is reasons which have to do with the exterior environment that children are raised in.

The fact that women will be able to get pregnant at any point in time because of a lack of menstrual cycle (or, at least I assume that's what you intend) will raise the number of pregnancies more significantly. However, that also isn't going to raise the number of pregnancies. Methods of controlling childbirth is by no means a recent innovation. Not to mention that there are large portions of world history where women were trying to have as many children as possible. Childhood mortality rates are historically quite high, they've only dropped recently as a result of superior medicine and once superior medicine exists, birth control becomes easier.

  • $\begingroup$ Birth control tends to be motivated by a wide variety of issues as you previously mentioned. My alternate humans also live in a sexually liberal society and are capable of safely producing over 6 children in a single pregnancy. Would these attributes cause any differences? $\endgroup$ Feb 18, 2020 at 1:24
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    $\begingroup$ @Hiccaries Sextuplets are rare in our society, but it's possible to occur. If you mean to say that the standard birth is sextuplets, that would have a much larger range of consequences and really would merit it's own question, especially since that condition wasn't included in your original question. $\endgroup$
    – Halfthawed
    Feb 18, 2020 at 1:38
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    $\begingroup$ As unplanned pregnancies are still common, I would think that being able to get pregnant at any time (vs the normal, somewhat small window), would either greatly affect the pregnancy rate, or greatly change the way people think about unprotected sex. $\endgroup$
    – Mars
    Feb 18, 2020 at 6:20

Pain "Natural pain" during sex is really not that natural for most people. Sure, some people have medical conditions which can make sex painful, but on the whole it's not painful, and enjoyable, so we can dismiss this point, as it isn't significant over the population. Pain during childbirth is not something most look forward to, but the vast majority of people who want kids will happily go through a few hours of pain for it, and I doubt many child-free people would cite this as their main reason. Pregnancy, on the other hand, is much more disruptive. Especially with most women working in the west, pregnancy and post-partum effects can interrupt a woman's other ambitions in life (namely her career) and the finances of the family. Since you have said pregnancy has no negative physical effects on your species, the mother will be able to do all her normal activities up to and after the birth, accounting for caring for children.

Genetic Factors For a population to remain relatively stable, each generation must remain the same size as the previous, meaning you usually want as many children to reproduce as adults are needed. Using a mammal-like mating system, that means at least 2/3rds of your children should either die before maturing or spend their lives having never reproduced. Ways to reduce this would be to require 3 or more parents, or to have sterile children, like ants. These sterile children should benefit the family genetically just as much as fertile children, or eventually they will be weeded out of the gene pool. If you require 3 or more parents to reproduce, not only do you reduce that statistical number of 'wasted' children, but you can also use a societal struggle to find a group of 3 or more who are happy together, which will limit the rate of reproduction, and may explain why many never end up reproducing. Since pregnancy has no negative effects on the mother, there is no reason to rush it. Pregnancy could last many years, as this would be beneficial to the mother as she wouldn't need to rush to get nutrients to feed 6 or more growing babies at the same time. Long pregnancies obviously mean that each woman can have fewer pregnancies throughout her life.

Societal Factors If your species lives in a modern society, societal factors will likely play a large role in family planning, as they do with humans. A very large factor for many couples is finances. Even if potentially you could provide for another child, sharing resources means that the children you have will have less. (£10000 goes further with one child than five). This could mean that low income families choose not to have children, or middle income families have just one 'litter'. This may also lead to some families abandoning some of the young, like many ancient cultures did with daughters, so that they would have just one or two at a time. Also related is the financial independence of youths. Even if they are able to reproduce at 10, they may not be financially stable for much later. This would prevent them from having their own children until older (most people don't have kids at 16-20, even though we could), but also delay their parents from having more children, as supporting two 'litters' at the same time would be a huge strain. Education could continue until they are 30 or so. Other cultural factors, such as shaming people for reproducing without passing a milestone (we have marriage and/or college, they could have whatever suits them). Perhaps one of the parents are expected to be a full-time caregiver, and having external childcare is shamed. Perhaps they have times of the year, or even periods of many years, where it's taboo to reproduce. Society is a great way of changing a population, and can allow some very creative worldbuilding.

Other Resources Most animals don't take pain, finances or societal shame into account when they reproduce, they just do. The population increases until competition (violence), lack of food/water, predators or spread of diseases due to close proximity balances out with their birthrate. If your species does not have technology (mainly contraception), this may be the way the population is controlled.

Summary No. In humans as we exist now, there are many other factors which cause us to make choices on reproduction other than pain.

  • $\begingroup$ I really don't think the first point can be dismissed. It's a fact that every humans first time engaging in sexual intercourse is somewhat painful and discomforting without practice. These humans have no such inhibitions. $\endgroup$ Feb 18, 2020 at 14:08
  • $\begingroup$ @Hiccaries - humans are unusual mammals because our males don't have any barbs on their penis. bbc.co.uk/news/science-environment-12689692 So there are plenty animals for whom sex is always uncomfortable (at least for the females) and it doesn't stop them breeding, $\endgroup$
    – DrBob
    Feb 18, 2020 at 16:33

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