Chapter 131 A Side-Story on the Gender Ratio
Edited by: Kanaa-senpai
In addition to my shadow, the Librarian, a security guard was now tagging along. We passed through a doorway protected by a mystical object that practically screamed “danger.”
The corridor housed an altar that looked like it belonged in some dark ritual, and a hexagram tapestry hung from the wall. I felt like I was staging a raid on a cult headquarters. If this wasn’t just some demonic display of bad taste, then it was a ward designed to repel anyone the library found “distasteful.”
However, the moment we crossed a certain threshold, the oppressive atmosphere evaporated. I didn’t even need to keep my ID pass visible anymore. The decor shifted, taking on the cozy feel of a private residence.
”Maybe traps are just useless for anyone who can actually make it this far,” I muttered.
I passed through one final, creepy room where I felt the prickle of phantom eyes on my back. I eventually reached a small archive.
The books here weren’t locked away like the others; they were just tossed around. Piles of unbound page-bundles formed literal mountains on the floor.
”There’s nobody here but me,” I said.
A half-eaten potato sat abandoned on a desk, shriveled and dry where someone had taken a bite. A fork was still stuck in a lonely sausage. Yet, right next to that mess, a fountain pen and an inkwell were lined up with obsessive, surgical precision.
It gave me a weirdly disjointed impression.
”Return this book to the ‘Rare Finds’ shelf; it’s a bore. – The Director.”
Was this a note from Gretel? A reminder was tucked into a book she’d been in the middle of reading. The archive felt lived-in – it smelled of actual human occupancy.
As I sifted through the abandoned piles to check the titles, one caught my eye. It was a thesis regarding the reasons behind the skewed gender ratio¹. The Librarian looked physically pained at the prospect of me reading it. When I asked why, she mentioned it had been relegated to the archives because they feared it might “offend a male’s sensibilities” should one ever see it.
”I thought this was the world’s greatest mystery, but they’ve known the answer for nearly a century?” I asked, flipping through the pages. “There are so many foreign names in the contributors’ section. Man, humanity really pooled its wisdom to crack the secret. What a beautiful era of cooperation… wait, no. They just used ‘Mystery’ to literally peep at their ancestors. That’s cheating.”
They didn’t deduce it; they just watched the playback. Naturally, I wasn’t about to get my feelings hurt, so I dove in. It was dense. An hour vanished just trying to parse the first few sections.
”I’m beat. My head’s killing me,” I groaned. “This is way too heavy for a high school grad. I don’t know the first thing about reading a thesis. And why is the font so tiny? This has to be harassment.”
”Please, enjoy some tea and sweets,” the Librarian said.
”Oh, uh, thanks,” I replied.
She had been standing the entire time.
”You can sit, you know?” I offered.
”I appreciate the sentiment, truly,” she said. “However, these are my duties.”
”Right. I forgot,” I muttered.
Unasked-for kindness was just a hassle here. A servant is furniture. Background noise. A tea-serving robot. A wall to talk at.
Guilt and sugar swirled together on my tongue. The quality of the sweets in this library was insane – maybe because the brain needs high-grade glucose to process this heavy lore.
* * *
The conclusion was clear: the gender ratio gap wasn’t magic. It was just evolution.
The first half of the paper covered male ecology as a preface; the second half detailed why the ratio became so lopsided. However, since it tried to explain things without assuming knowledge of genetic engineering, it was a nightmare to follow. I spent the rest of the night obsessed, borrowing memo pads from the Librarian to reconstruct the “science” using what little I knew.
Ultimately, I learned that the humans of this world were once exactly like the humans I knew. The divergence happened mid-stream. The gist was essentially this:
The male of the species is a failed design. Like a cargo ship with no freight, there is no purpose to his existence unless a female boards. He is, at best, a glorified errand boy.
I didn’t quite get the overarching goal of the thesis, but it opened with a bombshell that would make any modern guy turn beet-red with rage. According to the text, the male fell into an evolutionary dead end. No further progress was possible.
The history of the “Minority Male” dates back to the prehistoric era. In this world, the male-to-female ratio among great apes was originally one-to-one. Early humans shared that same ratio. However, a long time ago, our human ancestors nearly lost their entire male population. The count dropped to a mere one or two individuals for the entire species. For hundreds of generations, they were forced to inbreed within that impossibly narrow gene pool.
As for the cause? Apparently, the genes responsible for s*xual differentiation just didn’t “mesh” with the genetic blueprint of the newly evolved human race. Whenever a human was born male, they were inherently “weakened.” They either failed to develop or were born with severe malformations. It was a sudden, catastrophic failure that hit like a wall at a certain generation.
The trigger was identified in great detail: a pandemic during an interglacial period. As global temperatures spiked, a worldwide “disease trend” swept through all living things. A virus hijacked the cells of the great apes, rewriting a tiny sliver of their genetic code. It caused their brains to swell, making them smart enough to master fire – but it simultaneously rendered the males frail and puny. At that time, intelligence was bought with male vitality.
This kind of viral genetic integration is actually pretty common. In humans, for instance, the skin’s ability to retain moisture is apparently a gift from an ancient virus. Regardless, “Humanity” and “Male” became fundamentally incompatible. Being born as a man meant carrying a genetic curse of deformity or stillbirth.
In that era, many other species managed to recover and thrive despite extreme s*xual dimorphism. Some crustaceans and worms are classic examples. In extreme cases, there are fish where the female “hosts” a male who can’t survive on his own, exchanging him with other females like a shared resource during mating.
But for humans, it was a total failure. Out of some lingering biological stubbornness, a few “normal” individuals were still born… but the curse was spreading faster than they could adapt.
If you’re born a man, you’ll die before you hit puberty.
But women can’t breed alone.
The women of that era reached a desperate conclusion: “Dammit. Why weren’t we born as hermaphrodites? Actually, we never should have given up as*xual reproduction in the first place. Fine, let’s do this: we’ll just use His Majesty the Phallus² as a tool for mating between women.”
And that was that.
* * *
How did it come to that? Well, let’s look at the situation.
The extinction of the males was “gradual,” technically – it took several centuries. With every generation, the males became more fragile. They got smarter every time they survived a pandemic, but the number of stillbirths skyrocketed. The new generation of males dwindled across the globe. Like a shoddily built house collapsing on a delay, the viral time bomb in their DNA finally detonated after a few hundred years.
Humanity was just another “failed project” being erased due to a blueprint error. Eventually, the survival rate for males reaching adulthood bottomed out at 0.1%. Early humanity was reduced to tiny clusters of a few thousand people. Back then, the standard for a “desirable” man was simple: How many healthy boys can you sire? If one man could only produce one viable heir out of a hundred tries, and another could produce ten, the latter was chosen every single time.
The male genome began to condense. And finally, at the absolute brink of extinction – literally by a hair’s breadth – the genes for a man who could actually be born and reach maturity managed to “stick.” It was a total gamble. As a result, the entire male genetic legacy of the human race was funneled into just a few specific bloodlines.
Humanity’s new mission was clear: Protect these male genes at all costs.
But then, things got even messier. These males were miracles. If their bloodlines were diluted even slightly through crossbreeding, they reverted to being “defective.” It was a precarious, miraculous balance. Each man was standing on an impossibly thin pillar of stability. If you tried to “blend” different male lineages, you just ended up with stillbirths again. The male bloodline had to remain concentrated.
Simultaneously, a second problem reared its head: genetic disease. It was a nightmare catch-22. Crossbreed, and the males die in the womb. Inbreed, and you’re hit with a wave of hereditary disorders. In the end, the genetic diseases were considered the lesser of two evils. People were forced into a philosophy of pure-bloodism.
The mechanics of genetic disease are simple. Relatives share similar DNA, meaning they carry the same recessive traits. Breed them, and those traits manifest. The bizarre, grotesque features that humanity had buried deep in the “recessive” vault began to surface. It was the “Dark Side” of the genome, rising from the DNA graveyard.
Death arrived with the face of a monster.
”Hey there, humans! Long time no see. I went ahead and reversed the joints on that baby’s legs. Pretty cool design, right? Don’t worry, I’ve got plenty more ideas where that came from. Let’s be friends again!”
”Get out,” I whispered to the empty room.
The “evolutionary savings” they’d built up were wiped out. All the “bad traits” they’d suppressed were unleashed from the cage of natural selection. Whether it was a boy or a girl, they were born riddled with disorders. They were headed for extinction again. But you can’t ask for “diversity” from a male. These were the only male genes that actually worked. The only ones that could make it to birth.
The game was rigged. A total “trash-game”³ experience.
But unfortunately for the universe, humans are the kind of creatures that thrive on playing trash games. Just like a certain legendary Lieutenant. People chose one specific bloodline from the survivors. Then, they mated like their lives depended on it – because they did. Even when incestuous defects killed the children, they kept passing the baton through the few who were born healthy. Normally, a population that inbred would be wiped out, but they dug their heels in.
It was likely during this period that humans regained certain primitive traits as a throw-back to their ancestors. Mutations must have been popping up everywhere. Miraculously, humanity outran the genetic diseases and emerged as a new species. They completed a second “Great Trek” to bury the broken traits back into the recessive vault.
And thus, the lineage from a single “Adam” became the fixed standard. These male genes are incredibly “hardened.” I don’t know the exact mechanism, but the genetic data is essentially under a total “lock.” In my old world, men and women traded DNA to make a child, so the kid was a mix. But here? The male genetic info is aggressively exclusive. The female’s DNA can’t touch it. No matter who he has a child with, the “Male Specification” part of the blueprint cannot be rewritten.
It was a specialized genetic shift, a biological defense designed to shield males from random mutations.
In this world, mutation and diversity among men are non-existent. Evolutionarily speaking, every male is a perfect clone – essentially no different from an amoeba.
Of course, their appearances and personalities vary by nationality and race. For ages, this led people to believe that men possessed genetic diversity, but it was all smoke and mirrors. Apparently, something in the female genome triggers these superficial changes, masking the underlying uniformity.
Females, by contrast, are genetically rich. They evolve by mixing with the dormant female traits carried within the male genetic code. In this system, the male is nothing more than a vessel – a ship called “Sperm” designed to deliver the cargo of reproduction. To borrow a line from the top of the research paper: we’re just couriers.
A biological bridge for lesbian procreation.
In short, we are the stewards of “yuri pregnancy⁴.”
What a bizarre way to live.
Now, this “New Humanity” eventually blanketed the entire Earth, but at first glance, these “errand-boy” males were riddled with bugs.
Perhaps as a tax for such reckless evolution, our ability to recognize female-side genes became fundamentally broken. It’s more than just ignoring the traits sleeping in our own DNA; we’ve reached a level of top-tier idiocy where we can barely even distinguish between the actual women standing in front of us. That common complaint – that “all women are the same” – literally traces back to this glitch. From our perspective, individual differences are nearly impossible to perceive. We’re just deliverymen; we don’t care about the contents of the package, only the status and wealth of the destination.
This reality is most obvious in our total indifference toward having multiple partners. Conflict between men centers on status or “purity of heart.” No one competes over who can father the most children. Why bother? It’s the same result no matter who does it. Our collective mindset is basically: “Let the other guy handle it.”
* * *
That explains why male DNA is identical worldwide. The second half of the paper covers why the gender ratio is so horribly skewed. It’s less about genetics and more about the raw mechanics of population growth.
When competition between males drops, a species naturally trends toward a female majority. This is a universal constant, regardless of the world. The paper cites several animals as examples, providing a simple diagram to illustrate…
Imagine a group of ten humans.
Let ○ represent a male and ● represent a female.
○○○○○●●●●●
After a year of everyone getting enthusiastically knocked up… Squelch.
○○○○○●●●●● + ●○●○●
The population grows to fifteen.
Now, compare that to the broken ratio of our world. If we lowball the estimate to one man for every nine women, it looks like this:
○●●●●●●●●●
If that one guy spends his life enjoying a harem fantasy, the next generation looks like this:
○●●●●●●●●● + ○●●●●●●●●
The total jumps to nineteen.
Compared to the balanced group, this population grew by four extra people. Over time, this piles up like compound interest, creating a massive gap in reproductive power. This isn’t just a human thing; if one group reproduces faster under the same conditions, the more fertile group will naturally take over. Females who give birth to more females will dominate the gene pool. Conversely, those programmed to produce an equal number of sons and daughters will slowly dwindle until they vanish entirely.
This fits the “selfish gene” theory perfectly. Normally, there’s a counter-balance: to spread your own lineage, you’d want to produce “high-value” males to outcompete others, pushing the ratio back to 50/50.
But this world has a specific problem.
The males themselves have zero interest in passing on their genes. Whether it’s me or some other guy who fathers a child, the genetic result is identical. There’s no biological incentive to work hard at reproducing. Why waste your life force on mating when the “contents” are the same anyway? If the child is a clone of the collective regardless, there’s no point in burning resources to do the deed yourself.
Sure, men still have an instinctual urge to see their kind increase, but it’s more efficient to maintain a high social status and bully the other guys into sleeping with a hundred women each. From the perspective of spreading identical DNA, that’s just smart business.
To a man, another man is like a “copy robot⁵” from an old sci-fi manga – except the robot is just as much of a slacker as the original. If you have too many men, no one mates. They just try to pawn the job off on someone else until the population collapses.
The mothers who tried to produce sons to spread their line are left devastated. Their sons leave nothing behind. The more males a female produces, the higher the chance her lineage ends there. She has no choice but to have daughters. This is why the gender ratio stays skewed forever.
You’d think if just one male got motivated enough to sleep with a few hundred women, he’d break the system. But mathematically, that’s a sucker’s bet. The paper proves it with a mountain of formulas showing that the best strategy for a female to pass on her genes is to avoid having sons entirely. I couldn’t understand the math symbols, but the conclusion was clear.
In short, the male genome is as sluggish as a corrupt bureaucrat at the end of a dynasty. If we increase in number, we stop reproducing until the ratio swings back.
”Why should I do it? Let someone else have sx… What a drag. It’s all the same d*k anyway, just attached to a different guy. Oh, the community is going extinct because there are no other men? Fine, I guess I’ll do it…”
The “sweet spot” where that reluctant motivation kicks in? One man for every thousand women.
Scientifically, that number feels wrong. You’d think it would be one in a hundred. But there are higher organisms in my previous life that followed a similar logic – like the fig wasp⁶. They’re insects – maggots, really – that are so resistant to genetic defects they can inbreed indefinitely and still produce healthy offspring.
I used to think a 1:1 balance was the “correct” scientific answer, the gold standard of nature. But nature doesn’t care about being “correct.”
…It was a fascinating paper. Some of it seems sketchy, and I don’t know if the science holds up, but it really makes you think – especially since females here are so much more resistant to genetic disease than in my old world. It means one day, I might actually end up in bed with my own daughter or granddaughter.
The author tried to act sophisticated by calling this a “research paper,” but let’s call it what it is: a degenerate manual for family-friendly smut.
”Papa… I want your baby. Incest? What’s that…?”
”Grandfather, I wish for a child. Please…”
”Great-grandfather, before you pass on, please grant me your seed. I beg of you…”
I can hear their voices calling from the future.
I suppose I should prepare myself for the immoral days to come.
—
Summary:
The protagonist enters a secure archive and discovers a long-hidden thesis explaining the scientific origins of the world’s skewed gender ratio. He learns that a prehistoric viral pandemic enhanced human intelligence but caused a genetic incompatibility that nearly wiped out all males. To survive, ancient women consolidated the species into a few specific male bloodlines, eventually overcoming mass genetic disease through a miraculous evolutionary ‘lock’ on male DNA.
The narrator reads a research paper explaining the biological anomalies of his world, where men are genetically identical and serve as mere vessels for female evolution. He discovers the mathematical reason for the extreme 1:1000 male-to-female ratio, rooted in male indifference and female reproductive strategies. The realization culminates in the narrator accepting his role in a future defined by biological necessity and taboo domestic relations.
—
Trivia:
- The Director’s name is Gretel, and she has a messy but meticulously organized workspace.
- The gender ratio wasn’t caused by magic or a curse, but by a prehistoric viral pandemic.
- Human intelligence (large brains) and the ability to use fire were direct trade-offs for male genetic fragility.
- The current male population all descends from an incredibly narrow gene pool (a few bloodlines).
- Male DNA in this world is ‘locked’ and does not mix with female DNA, ensuring the survival of the male blueprint regardless of the mother.
- The protagonist feels a deep sense of guilt regarding the Librarian’s subservient ‘furniture’ status.
- Males are functionally clones, meaning individual fatherhood is genetically irrelevant.
- The ‘yuri pregnancy’ concept implies females provide most of the genetic material, with males only acting as catalysts.
- The gender ratio isn’t just a quirk; it’s an evolutionary stable strategy due to male laziness.
- The narrator has memories of a ‘previous life’ where 1:1 ratios were the norm.
- The fig wasp comparison highlights that inbreeding is biologically viable in this world’s setting.
—
Character Insight:
The protagonist displays his intellectual curiosity and persistence, spending an entire night parsing a difficult thesis despite his self-admitted ‘high school grad’ limitations. His reaction to the history reveals a mix of cynical humor (calling it a ‘trash game’) and genuine empathy for the prehistoric struggle for survival. Meanwhile, his guilt over the Librarian’s treatment shows he still retains ‘old world’ moral sensibilities.
The narrator shifts from detached intellectual curiosity to a cynical acceptance of his world’s ‘degenerate’ reality. His internal conflict between his previous life’s morality and this life’s biological programming begins to dissolve as he hears the ‘calling’ of his descendants.
—
Behind the Scenes:
The author uses this chapter to ground the ‘Reverse Chastity’ trope in speculative biology and evolutionary theory, moving away from purely fantastical explanations to provide a ‘hard sci-fi’ backbone to the world-building.
The text parodies academic writing to justify ‘isekai’ harem tropes, specifically addressing the ‘lazy protagonist’ trope as a literal biological imperative.
—
TL Notes:
Notes:
• Gretel – Director and owner of the National Diet Library. A playful lady with an atmosphere of an ‘another world’ noble. Features rainbow-colored kaleidoscope hair. Refined, composed, but capable of extreme coldness toward subordinates. She possesses the authority to trigger the library’s ‘contract’ and automatic punishment systems.
Please bookmark this series and rate ☆☆☆☆☆ on here!
Edited by Kanaa-senpai.
Thanks for reading.
Leave a Reply