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Sex Ratios: What if the global ratio of males and females changed?

The ratio of men and women in the world is remarkably similar with males being only slightly more common than females. In some countries the ratio is slightly higher than others but it doesn’t change much and hasn’t over the course of recorded history. You can read more about the distribution of chromosomes and the reason why our gender ratio stays generally constant. It is really fascinating but I didn’t feel like rewriting it. I wanted more to consider what would happen if this golden ratio were to change. What if we the new Covid vaccine caused only female embryos to implant in vaccinated women? What if some new pesticide caused male embryos to not live to term? What if we suddenly lived in a world with 25% men and 75% women? How does society change when the ratio of men and women shifts?

In 2020, 101.69 Males were born for every 100 females. Men are born at a slightly higher rate than women and men have a shorter life expectancy which helps to minimize that gap especially among the older side of the population. Cities in Europe have noted a “man drought” with ratios of 45M:55F. With females being the limiting factor in reproduction due to the gestation period for pregnancy, it seems that a significantly higher ratio of females to males would be the evolutionally expectation. One male can reproduce with multiple females to boost reproduction rates.

It seems that a higher ratio of either gender would throw our societal expectation of monogamy out the window. Would it become a class based society where the more scarce gender has a heightened social status? Would you see the societal relationship norm become polygamy or polyandry? Would we see a rise in homosexuality rates among the more populous gender? Of course my scenario is considering only biological sex and not gender. Perhaps we would see a greater rate of transgender people. A nongenetic gender drift, if you will.


We would probably see societal problems and attempts in government enforcement. Consider the impact of China’s son preference as it related to their “one child” policy. As a result, there is a large male surplus in China, South Korea and several other Asian countries.

I’ll bet we would see new scientific initiatives to find medications to alter the birthrate or allow parents to select the gender of their offspring? I’m sure we would see an increase in sexism? If males were suddenly more valuable, perhaps we would see them relegated to household tasks instead of playing with guns and sending them off to fight our wars. I can only assume that females were seen as more valuable which is why society has tried to keep us safer. I think back to the movie The Titanic, as the ship sinks and the crew yells women and children first. Clearly there is a higher value on the lives of women and children, perhaps this is because women are the caregivers for children and their survival may be linked to that of the children.


Thankfully, we don’t have to worry about a long term biological sex deficit due in part to Fisher’s principle. The basis of this principle is the following:

  1. Suppose male births are less common than female.
  2. A newborn male then has better mating prospects than a newborn female, and therefore can expect to have more offspring.
  3. Therefore parents genetically disposed to produce males tend to have more than average numbers of grandchildren born to them.
  4. Therefore the genes for male-producing tendencies spread, and male births become more common.
  5. As the 1:1 sex ratio is approached, the advantage associated with producing males dies away.
  6. The same reasoning holds if females are substituted for males throughout. Therefore 1:1 is the equilibrium ratio.

It sounds like we’ve seen little change to our gender ratio but I’d like to thank you for once again entertaining another random shower thought from your favorite blogger.

What other effects do you think we would see if the sex ratio changed?

What do you think would happen if the transgender rate changed significantly and it suddenly became unfashionable to be either male or female? With if anyone with the means to purchase hormones and pay for gender reassignment decided to do the ol’ swaparoo.

I apologize in advance to my trans readers, this post is probably horribly insensitive. I don’t mean any offense, I’m just throwing random ideas out in the same manner that they exist in my head – the crudest form.



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I think we are moving to a more open way of being in relationship. Its a lot easer to be homosexual now then it was in the not to distant past. Its a lot easer to be trans now. Its a lot easer to be interracial etc.

Given this, the further down the road we go, if there where a sizable ratio shift, I think we would see more people hooking up with the same sex majority and the reproducing thing would happen in a practical way, i.e. sperm banks on the one hand, and seragate carriers moms on the other.

Would the minority group come to be more valued? Possibly, but I don’t think it would last long. It would turn into people competing for them which would make them insufferable, and given that we are headed to direct brain computer interfaces and AI anyway, it wouldn’t be but 10 seconds before the majority turn to far more interesting AI based relationships than put up with a prima donna minority human, assuming they weren’t in a fulfilling gay relationship that is.


Hello, there is an amazing Polish film for this topic. The movie is called Sex Mission and it’s a comedy. I highly recommend watching it for everyone 🙂


Good day. I have the film only in the original with English subtitles. I will send I know the download link.


Thank you very much Emma for this blog. As a husband, I have lived in the chastity belt for ten years. It was our joint decision. And it was free, rather influenced by circumstances. it felt like it was so right. Only you and your blog could explain to me why the feeling was right 🙂


Some info about this movie is here: http://sfkadr.com/en/movies/19/sexmission.html It’s very difficult to find official video with english subtitles, rather one must search for it on amazon or similar places.
By the way – despite the fact that it’s a fictious comedy this movie is considered very sexist. Now it’s treated as one of the ‘polish classic movies’ but I believe no one would make such movie nowadays.


Emma, I don’t think there will ever be a significant gender imbalance for the reasons you give, but I think it is fun to think about different scenarios as premises for possible erotic sci-fi stories. As a male with a strong submission kink, I like the fantasy of a world in which women gain greater sexual power because there is a surplus of men. In that world, polyandry would be the norm, with women able to have multiple husbands and male concubines. Women would be able to put more time and energy into their careers because men would take on domestic labour and childcare roles.

Yesterday, I happened to see a poll about a gender imbalance that actually exists: a sexual attractiveness imbalance. Women and men were asked to rate members of the opposite sex for sexual attractiveness. I forget the exact numbers, but a majority of the women were rated by men to be sexually attractive. However, the women rated only a small minority of the men to be sexually attractive. This, of course, fed into my cuckold fantasy of women taking beta men as husbands who would be supportive and obedient domestic partners, while having some of their sexual needs met by a small pool of unattached alpha males.

There is another real life phenomenon that feeds into this fantasy. For environmental reasons that are not yet understood, many males of various species, including our own, are being born with undersized penises and low sperm counts. This should be cause for serious environmental concern, and I don’t wish to make light of it by reducing it to a sexual fantasy. But I must confess that it feeds into my cuckold fantasy about emasculated males serving women in domestic roles while a virile minority serves them sexually.

By the way, have you ever read any of the sci-fi novels from Iain M. Banks’ “Culture Series”? The Culture is a futuristic society with an extremely high level of technological development that makes possible an extraordinary level of individual flourishing, allowing people to freely explore different kinds of experiences. In the Culture, people regularly transition from one sex to another, so as to be able to experience for themselves the full range of sexual possibilities. I find that to be an intriguing fantasy.


Culture novels. So good.

As happy as I am to be alive now, I would love to live in a time where you could morph into different forms.


If males were suddenly more valuable, perhaps we would see them relegated to household tasks instead of playing with guns and sending them off to fight our wars.

I strongly suspect that if there were more women than men, and consequently they formed the larger majority in governments, that there’d be far less war in the first place!


It’s nice to think so.

What do you think? Please leave a comment.x