I'm working on something about an all-female human society modeled on real single-sex parthenogenetic species like the famous Whiptail Lizard. A few of the things I'm borrowing from Whiptails are:

  1. Daughters are not true clones of their mothers, so there is some genetic diversity between generations.

  2. Individuals still have (non-reproductive) sex, and this is in fact plays an important role in triggering parthenogenetic reproduction. Here's a couple of fascinating papers about this behavior in parthenogenetic lizards. Some creative license in needed in imagining how this would translate to mammals. My thinking is that sexual stimulation during ovulation causes the release of hormones that in turn trigger parthenogenesis.

  3. The evolutionary divergence from sexually reproductive humans is fairly recent, and the species remains similar in most other regards. (I'm aware that parthenogenesis would be a highly implausible natural mutation in humans for all sorts of reasons, but just roll with me.) This means there may be some vestigial traits and behaviors, like in the above example of non-reproductive sex.

Given all that, I'm trying to figure out what the most common family/household structure would be. Obviously humans are diverse and there will always be exceptions to any rule, but in the real world marriage is very nearly a cultural universal. I'm not sure that would be true for parthogenetic humans.

People would still have sexual and romantic relationships, as an evolutionary legacy of sexual reproduction, but since those relationships wouldn't produce shared children I don't think they would have anything like the same significance. Marriage only carries the weight that it does because sexual reproduction allows unrelated people (and thereby their families) to become relatives by mingling their genes.

But the deep evolutionary logic of "I would gladly give up my life for two brothers or eight cousins" still applies in a world of parthenogenesis. So my current thinking is that lineages of related women, rather than sexual partners, would be the most common basis for the family. This is actually somewhat similar to the practice of the Mosuo people from the link above, who live in households composed of female relatives and their children, with romantic and sexual relationships occurring between households rather than within them.

What do you think? Would marriage still be nearly universal among parthenogenetic humans? Would it exist at all?

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    $\begingroup$ Welcome to worldbuilding. Please note that we don't give out suggestions on open ended question like this, where you are basically asking to extend a list. Give us a well defined problem with a way to decide the best answer, and we will try to provide one. And this is the last point: real humans reproduce sexually, and there isn't a single social organization all across the world. Why would it be different for your humans? Please read the help center for more info $\endgroup$
    – L.Dutch
    Jul 8, 2021 at 3:01
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    $\begingroup$ Thanks for the heads up! I should have read the rules first. Should I delete and repost a more specific question? $\endgroup$ Jul 8, 2021 at 3:19
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    $\begingroup$ You can edit this post to make it fit our standards. At the bottom there is an "edit" function which you can use. $\endgroup$
    – L.Dutch
    Jul 8, 2021 at 3:21
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    $\begingroup$ Okay, I just edited it. $\endgroup$ Jul 8, 2021 at 4:05
  • $\begingroup$ "Would it exist" is an opinion, or a prediction of how characters would behave in a fictional situation, at best; could it exist is answerable (and so obvious that the question needn't be asked at all). $\endgroup$
    – rek
    Jul 8, 2021 at 22:58

4 Answers 4


Speaking sociologically, human marriage institutions aren't for the production of children (which is a relatively simple procedure); human marriage institutions reflect the fact that raising a child to adulthood is a tremendous investment of time, energy, and resources. It's almost impossible to be a single parent and simultaneously generate the resources needed to feed, clothe, and house children. Single parents need family or nannies or creche/kibbutz-type daycare because children need near-constant watching-over.

With that in mind, parthenogenetic societies could still have marriage-like institutions in order to share the burdens of childcare. I suspect such a society would gravitate more towards small groups — four to six mutually committed individuals — because slightly larger groups are more efficient than dyads without sacrificing intimacy. But if intimacy is not a big issue for your people, they would almost certainly lean towards a kibbutz type system of community child-care, and then marriage institutions would have no real purpose in the society.


Around 2-5% of people would probably want to marry.

Since they're a recent evolutionary divergence from humans, they would likely still have similar ratios of heterosexuality and bisexuality and lesbianism.

As such, the majority would be (unfufilled) people who wanted heterosexual relationships and a small minority would be eager for relationships and annoyed at all the strange seemingly asexual women.

  • $\begingroup$ I think situational homosexuality would be the norm for most people, just as it is in many single-sex environments in the real world, with the relatively small number of people on the far left of the Kinsey scale living as functionally asexual misfits. $\endgroup$ Jul 8, 2021 at 10:23
  • $\begingroup$ Outside of highly stressful situations like zoos and prisons where people are forced together and sometimes rape each other for dominance, most single sex environments don't produce sexual orientation changes, e.g. all girls or boys schools. $\endgroup$
    – Nepene Nep
    Jul 8, 2021 at 10:45

Define "marriage"

If this is a recent development, then our starting point is, basically, today. What is "marriage" today?

  • A socio-legal contract between two individuals, previously of separate gender but today of any gender, that establishes the relationship between the parties for the purpose of protecting earnings, assets, and the parental rights over children/minors.

  • A socio-religious agreement between two individuals, still predominantly of separate gender (but this is changing), that establishes the credibility of the relationship within the religion and within society in general. I'd need to do some research into it, but my gut feeling is that a religious marriage is today still deemed "more credible" than a marriage by civil authority (but I honestly admit that may be an ignorant bias due to my own religious upbringing.)

  • A culturally-based commitment between two (or more) people for emotional and/or economic benefit (aka, "living together"). Some localities consider a long-term commitment to this kind of relationship to constitute a "common-law marriage," meaning that eventually legal protections and expectations attach to the relationship due to the long-term commitment looking a whole lot like a civil or religious marriage.

  • And at the other end of the scale... we have "shacking up," which can be a serious relationship with emotional and economic benefits, but can also be nothing more than a long-term "one night stand" where little is gained other than cheaper rent and a readily available date.

Where would a parthenogenic party fit in all this?

Such a person would still have been raised in the culture of "marriage" (aka, all that variety above) with locality-specific shifts due to culture (is our subject from one of the so-called "western civilization" countries? or would she be from an African or Australian tribe? etc.). The specific origin of our subject is not defined in your question, but it is important. A parthenogenic woman raised in Iran would have a very, very different set of choices compared to a similar woman raised in Berkeley, California.

However, we could make some simple assumptions

Using western culture as our starting point (I'm most familiar with it), and ignoring the more interesting unions (polygamy comes to mind), let's consider some of the "cultural pressures" that would affect the decision.

Shared Economics: Unless one happens to come from a wealthy family, it's almost impossible today to raise children on a single income.

Shared Chores: I've worked with single mothers who were raising their children, not only without a partner, but in a culture that doesn't regard single women highly. One such lady related a story of watching happy families driving to church services while she was outside chopping wood because there simply wasn't enough time to both chop the wood for heat and make breakfast and take care of her child to make it to services (which she dearly wanted to do).

Shared Emotional Strength: Humanity is a social species — and not simply because of the biological drive to propagate the species. We like to be together, to share experiences, to shout together in joy and to cry on one another's shoulders. Yes, there are the exceptional people who can live their lives alone on a deserted island and be entirely happy — but that would drive most of us bonkers. Few things are worse than achieving a victory and having no one to share it with who is totally invested in that victory and the individual's part in it.

And on top of this are...

  • Legal benefits and consequences to a recognized relationship. Here in the U.S., our tax structure has a "marriage penalty" (this, despite some circumstances that make marriage beneficial for taxes).

  • Social benefits and consequences relating to the children. While a great many children attend school having only one parent, having two is still considered culturally preferred.

  • Social stigma of both the parent and the child. This one will be one of the more powerful issues, but also the more difficult to define. Humanity is very good at not liking things that are "outside normal." It's a funny behavior, because "normal" has more to do with the habits and cultural perspectives we learned as children than they do an actual statistical average. Nevertheless, parthenogenic families can expect bias... even hatred... because they're outside of what the culture generally considers "normal."

And that issue deserves a bit of detail. The U.S. has taken great steps to recognizing a considerable amount of diversity, which could be said that we're redefining "normal" to have little or no meaning at all. Nevertheless, only a blind idiot doesn't recognize that the powerful habits of previous generations (male-female marriage, for example) are not at all gone... they've simply gone underground where the vocally violent supporters of both sides can't easily hear one another. In many ways, the nation is as divided as it has ever been — only the socially-acceptable public voice has changed. There's still a lot of work to do.

TL;DR, what's your point, JBH?

Marriage, meaning a meaningful and committed relationship (whether formally sanctioned with a piece of paper or not) will remain a significant component of parthenogenic families if only out of habit. All those non-sexual/non-reproductive benefits (and consequences!) still apply. And while after some time the world may recognize the non-necessity of a reproductive partner, it may never relax the economic, legal, and emotional conditions that tend to drive people together.

And on top of that, unless parthenogenesis results in an individual being substantially inhuman, that person is still a very social "being alone stinks" person.


From an evolutionary standpoint, in a species like humans it's convenient for the male to invest in the upbringing of his offspring, because it's his own genes moving forward in time. This investment means forming a stable pair with a limited number of female, ideally one, and raising the offspring. This is sort of the background for the concept of marriage.

However in a parthenogenic species like the one you describe, what would be the benefit for the non reproducing partner to invest time into a stable relationship? There are no own genes to protect and nurture. There will still probably be relationships based on mutual support, like there are couples without children in our world. But I don't think there will be a formal institutionalization of those.

  • $\begingroup$ There are no males! It's a single sex species just like the lizards. $\endgroup$ Jul 8, 2021 at 4:59

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