A person I know described to me their idea of a future world where the following developments will have taken place:

  • 2057: Cloning is ethically acceptable and easily achieved
  • 2117: The male-to-female ratio among humans is 1:100
  • 2135: Human males are extinct

However, in order for this to be credible, we'd need a good answer to the question:

How could the development of some kind of cloning technology (deliberately being vague here) be explained to result in the extinction of males?

If full extinction is not possible to explain (perhaps because of social factors in addition to or instead of scientific?), would relaxing the requirement help? Say, by allowing tiny enclaves of males or mixed population to exist.

  • $\begingroup$ I just cannot wrap my head around the basic idea behind this question. I get the first step -- cloning becomes a consumer option. But I don't see how the 1st step is linked to the 2nd -- what is the factor that skews the sex ratio so much? $\endgroup$
    – AlexP
    Commented Jan 14, 2017 at 3:16
  • $\begingroup$ @AlexP that's what I'm trying to find out :-) $\endgroup$
    – Jon
    Commented Jan 18, 2017 at 16:53

5 Answers 5


Short answer: it can't, sorry. Long answer:
Here's why.

1. The world is too big

A common fallacy among Worldbuilding questions, I've noticed, is the idea that technology emanates completely. People assume that when tech is developed - such as easy space travel - woohoo, the world is abuzz with spaceships, everyone is in the golden age, the world has completely changed!

Yet even today, in 2017 - about 200,000 years after the evolution of the modern human, and 12,000 years after the invention of agriculture - there are still hunter-gatherers in the remote jungle, 60% of the world doesn't have wifi, and there are billions without access to medical care - let alone clean water.

Even if the reasons I'm going to list below aren't factored in, and developed countries with cloning technology eliminate all males - there will be parts of the world where you don't see this change.

2. History had men and women

Men, in addition to women, are important. If men accomplished half of all historical achievements - likely more, considering sexism prevented many potential female leaders, generals, scholars, and more, from being able to contribute - then they will not be thrown out. People value both genders.

3. Not everyone will consent to change

There are parts of the most developed countries today that view topics like gay marriage, women's right to choose, and females in leadership positions as non-traditional, taboo, or sinful (FYI I'm not taking a stance on those topics, just stating a fact). Regardless of your views of those topics, it is clear that 100% agreement cannot be achieved. Many families (far more than 1 in 100, as the question says for 2117) will simply refuse to participate in any genetic modification, let alone removing males.

4. Personal preferences matter

Many people may accept cloning / genetic modification, but there is no reason for men to become extremely "unfashionable" in their eyes. Many parents / couples will choose to opt for masculine traits when designing / selecting offspring, because they may still be viewed as adequate or attractive.

5. Sexuality exists in addition to gender

No matter how many men you eliminate, there will be women - and, well, men - who will continue to be attracted to men. Reproduction aside, you can't take away what roughly half the population is attracted to and expect them to be attracted to themselves.

6. Cloning may be bad for the population

Direct cloning - using a person's DNA to fertilize them self - can result in multiple genetic disorders (mandatory xkcd reference on page 158 of the book What If). Additionally, genes spread across the whole population because they're "popular" - whether they belong to a celebrity, or they provide superior abilities, or desirable physical traits - will lower genetic diversity, which can be a problem in the long run.

  • $\begingroup$ Yes, women may have been prevented from contribution to history by sexism — but, on the other hand, there have been cases where women did contribute, and the sexist historians declined to record the events accurately.   See Rosalind Franklin and the women involved in the Mercury program. $\endgroup$ Commented Jan 15, 2017 at 1:56
  • $\begingroup$ @PeregrineRook I do not disagree; both are important to history, to culture - to humanity itself - so taking away one should not be able to happen. $\endgroup$
    – Zxyrra
    Commented Jan 15, 2017 at 4:26

I'm currently building a world where there are no more male humans. However, there are no more female humans either. All humans in this world are unisex and are infertile.

My current reasoning for this is that birthing machines were invented, which allow two people, who can't have a natural baby together, to have a child. The machine takes their DNA and mixes it and grows an egg and sperm, which it nurtures until birth.

Over time, more and more infertile people will be able to reproduce and increase the number of infertile people in the population. Over a century or so later (or longer), people will rely on these machines to reproduce.

At this point, genitalia will be redundant because it will no longer be used to reproduce, and it will go away -- both male and female, just like the appendix and tail did.

Cloning technology will not just make male humans extinct, it will also make female humans extinct.

  • 2
    $\begingroup$ Even if something is genetically redundant, it doesn't go away in a hurry unless it's become seriously detrimental. You cite the appendix as an example, yet lo and behold, people are still born with an appendix despite it being of no obvious use. Also, you seem to ignore the fact that people have sex for fun as well, which isn't covered by your argument here. True, more normally infertile people could reproduce; that's been true for the past century via in-vitro fertilization, artificial insemination, etc., and it sure hasn't shown any indication of eliminating males yet. $\endgroup$
    – Palarran
    Commented Jan 14, 2017 at 1:35
  • $\begingroup$ @Palarran Thanks for pointing that out. I know it's not a perfect explanation but it's the best I got with what little knowledge I have on the subject. Oh and I forgot to mention that the machines give the parents the ability to choose their children's genes, which could definitely speed up the process. $\endgroup$ Commented Jan 14, 2017 at 1:44

You can't get from cloning alone to extinction of men. You can make cloning only work on women easily enough. And that's pretty much a prerequisite for this concept to work. But cloning alone won't explain why you won't get men the traditional way: as a result of sexual intercourse. So you need a separate explanation.


You can have a disease that either kills men or causes infertility. The infertility could be in men, women, or both.

I've read this scenario. Don't remember title or author. If you're curious, I could ask on the sci-fi stack. Someone can probably identify it. It didn't explain much about the mechanism though. It handwaved the plague except to describe its existence.

If you just want to write about an all-woman society, this is probably the easiest way to get there. It's just believable enough to handwave the difficult parts as history. The other suggestions are better suited to writing about the evolution of society, as they are too unbelievable on their own. And someone here could absolutely help you design this plague in a new question. That would be a more focused question than this one.

Sex bots

More and more complicated sex toys and more realistic porn could make men and women feel less and less like the opposite sex was necessary for sex. Virtual reality porn. Why have sex with some unemployed pothead with obnoxious body odor and bad breath when you could have your ideal man? Especially since the employed guy with the potbelly and balding head would really prefer to have sex with a simulated supermodel. We could reach a situation where the population's falling. Governments use cloning to bolster the falling population.

And even if you don't want to write about sex bots, think of the fanfic.


In the most recent US election, women and men voted distinctly. What if that continues to grow? Once women can reproduce without men, it would be possible for women to revolt. Maybe they do.

The other day, I was searching something related to a post here and clicked through to a blog where the author identified murder as the number one male privilege. What if that view went from a fringe concept on the internet to a view held by a distinct minority? These modern Amazons could take their cloning process and form their own community. And then they could take over the number one privilege from men.

If you always wondered what a society built by lesbian serial killers would be like, here's your chance.


This could totally happen. In a human colony in space this would be optimal to maximize genetic diversity: Frozen sperm and all females. Lots of male genetic diversity possible in the freezer. All females maximizes population growth per available resource. If clones must still gestate in a female same logic applies: only females can gestate a fetus so more females means more population growth. If this is Brave New World and babies grow in jars that won't apply.

If your population is all clones one could get rid of males by 1: having a Y chromosome retrovirus that kills males. 2: having a population crash generally and a ban on cloning new males for societal reasons. 3. Clone tech must start with an unfertilized egg, so males out of luck.


Not likely: cloning as a technology makes females redundant, not males. As to why this is unlikely, in addition to excellent previous long answer regarding cultural, religious and other reasons, consider this: sperm banks potentially would make males redundant long time ago, as just a few tens of thousands outstanding male specimens could easily satisfy world's need in sperm with sufficient genetic diversity, but that never happened.


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