In a fictional earth-like world there are humans and a few magical human-like species. These species differ from humans in various ways. The most obvious difference is that they are entirely female, and the most profound difference being reproduction. I would like to know how differences in reproduction would be likely to manifest as differences of culture - specifically with regards to family structures and roles. How will the families of this species be different from humans, and why?

Answers should be grounded in scientific knowledge.

Species "Double Trouble" have male and female sexual characteristics, when they mate they will both become pregnant.


closed as primarily opinion-based by Aify, Hohmannfan, TrEs-2b, JDługosz, inappropriateCode Aug 9 '16 at 23:43

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ Both can become pregnant, or both always become pregnant? $\endgroup$ – John Dallman Aug 9 '16 at 21:19
  • $\begingroup$ Sorry, good question. Mating makes both pregnant; will edit. $\endgroup$ – inappropriateCode Aug 9 '16 at 21:29
  • $\begingroup$ "How will the families of this species be different from humans?" is not possible to answer with scientific knowledge because we have 0 scientific ways to get any sort of relevant data or information. It's your story, you can make them as different as you want them to be - your question qualifies as primarily opinion based, and I'm voting to close as such. Note - the above explanation also applies to the other 3 "influence of reproduction on culture" questions you've asked today. $\endgroup$ – Aify Aug 9 '16 at 22:29

My first thoughts on the idea:

Having both members of a couple pregnant at the same time would increase the need for assistance, outside of the couple, during this period. Cultures would likely have more closely supportive extended families or larger marriage groups, so that additional members of the group could provide assistance during and after pregnancy.

Your culture would also have a dualistic aspect, everyone would have a sibling of the same age from the dual births, effectively everyone would have a fraternal twin.

If this culture lacks effective birth control, both members of the couple would have an equal motivation to avoid unintentional pregnancies. The stereotypical male sexual strategy of multiple partners would not exist.

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    $\begingroup$ I like the points you raise (especially the latter about mating strategies), including the obvious one about everyone having a twin. But could you elaborate this with any context of how having a twin does or does not affect an individual? As presumably these effects would be greatly exaggerated in such a species. $\endgroup$ – inappropriateCode Aug 9 '16 at 22:17

Geometric families

As Josh pointed out everyone is born with a fraternal twin (barring accident or illness).
It would seem that you would have as strong culture around twins and what you twin does, whether this is conforming or rebelling against what the other is doing. The society would probably have a special name for those who have lost their twin, maybe being a "single" person is a stigma there.

It would also seem not uncommon for double twin marriages ie two twin siblings to marry two twins that are also siblings.

Double marriages would tend to create tightly knit extended families because when families are united in marriage they are actually united in double marriage.

It might also create a tradition of conformity, you grow up you twin who is like you, your parents, you siblings and their twins, you parent's twins who are like them and your parents' twins children who are also like you.

They would also limit the mixing of genes. In our world a if two children get married they usually marry into different families and so mix genes with two different families, in this model they would only mix with one more.

Finally it limits control over birth rates, unless you abort one child in a twin pair the only options are 0 kids 2 4 6 .... Aborting one child in a twin pair might stigmatize the survivor and so be unlikely, unless there was some movement to make it popular.


This would certainly change the family dynamic. The current family dynamic we have is based on ancient times where pregnancy was quite a risk for women and child mortality rate was high. As a result of this families develop in such a way that the pregnant wife could stay at home in relative safety prevent anything from happening too her or to the child. While the man leaves to work or go to war.

Naturally of course the family system would definitely very different since both married partners would be pregnant at the same time.

There are many options for how they Develope around this. One option is to have the married pair stay with the parents. In Traditional marriage both parties leave their parents to start their own family. But with your creature is they could instead move in with one of thier parents. And have the parents help them with their Mutual pregnancy. This could lead to large very tight-knit family Clans. Since the kids would grow up under same roof has their grandparents, aunts/uncles and thier nieces/ nephews.

It's also possible a form of twin marriages might develop as mentioned in the other answer, where one set of twins marries a second set of twins and moves in together. In this case they might take turns one married pair getting pregnant while their counterpart does not and tell the other pair has given birth.

Laws are probably develop regulating who can get pregnant when. One of the reason why woman in Warfare was uncommon in ancient times was because you didn't want to threaten the Next Generation in this generation's War. So you would want pregnant woman and women to be far from the battlefield. Of course in this case both married partners will be getting pregnanate. To prevent you from having to send entirely pregnant Fighting Force to battle. That would probably regulations in placed for rent in your country or city was threatened with war.

Sex would be a lot less casual at least until the invention of birth control. Traditionally speaking men take sex a lot more casually than women that is because they don't have to necessarily deal with the consequences of pregnancy and they run no risk of death by childbirth. However for your features both sides run these risks so they would take sex equally seriously at least until the invention of birth control.


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