Throughout human history, 40% of men have reproduced compared to 89% of women. Why was that, and is it still true that more women than men reproduce?

Question

abc3643 · Accepted Answer

I just wanted to add this: It's the peer-reviewed journal article which is the basis for this question...

The article is titled:

"A recent bottleneck of Y chromosome diversity coincides with a global change in culture"

and is from the April 2015 issue of the journal is Genome Research .

The Table of Contents for that issue:

https://genome.cshlp.org/content/25/4.toc

The article is free to read and I include the abstract further below.

A recent bottleneck of Y chromosome diversity coincides with a global change in culture

Monika Karmin, (and 99 co-authors)

Genome Res. April 2015 25: 459-466; Published in Advance March 13, 2015, doi:10.1101/gr.186684.114

This is a link to a PDF of the article and another link to supplementary materials for the article:

https://genome.cshlp.org/content/25/4/459.full.pdf+html?sid=231a6bd0-2287-4d73-aa30-6b78835dd33d

https://genome.cshlp.org/content/25/4/459/suppl/DC1

This is the abstract of the article (but I added the boldface):

It is commonly thought that human genetic diversity in non-African populations was shaped primarily by an out-of-Africa dispersal 50–100 thousand yr ago (kya). Here, we present a study of 456 geographically diverse high-coverage Y chromosome sequences, including 299 newly reported samples. Applying ancient DNA calibration, we date the Y-chromosomal most recent common ancestor (MRCA) in Africa at 254 (95% CI 192–307) kya and detect a cluster of major non-African founder haplogroups in a narrow time interval at 47–52 kya, consistent with a rapid initial colonization model of Eurasia and Oceania after the out-of-Africa bottleneck. In contrast to demographic reconstructions based on mtDNA, we infer a second strong bottleneck in Y-chromosome lineages dating to the last 10 ky. We hypothesize that this bottleneck is caused by cultural changes affecting variance of reproductive success among males.

====================

Here's my hypothesis about the second "bottleneck" mentioned in the abstract. ...

First, some background. ...

This occurred shortly after the invention of agriculture which is about 12,000 or so years ago (pretty much when recorded history begins). Once agriculture is invented, civilization begins because humans stop being nomadic hunter-gatherers. This is called "The Neolithic Revolution".
https://www.history.com/articles/neolithic-revolution

With civilization, 2 things are going to occur:

1. You will get stratification among members in a society. In small nomadic hunter-gatherer clans, such stratification is near non-existent since the members of the clan must co-operative to survive. Sure, you might have a leader, but the leader only defends himself and is easily killed or otherwise deposed by the other members of the clan if they don't tolerate him anymore. But, with that stratification within a society after agriculture is invented, the leaders have layers of protection (such as guards). And, naturally, women will be attracted to such men because they are safer in the sense that he is more likely to be able to keep her and her children alive. Of course, such men also often get whatever women they want and often have many women. There's a reason why, in the Bible, you get lots of leaders like Solomon having hundreds of wives or concubines.

2. And, since agriculture means that the society is no longer mobile, protecting the society's territory becomes more critical. So, armies come into being and, with them, of course, is eventual conflict with competing societies. Since armies need healthy young men, they are the ones getting killed and not passing on their genes. Those who don't fight, like the leaders, live to reproduce. It's evolution in action.

This latter comment is reminiscent of the Kzinti species in Larry Niven's science fiction novels. The Kzinti were a feline-like warring race. They often wanted to go to war with humans but were unfortunately for them to gung-ho about it and they'd lose (at first because humans got assistance from other species who didn't care for the Kzinti either). After so many lost wars with humans, the more violent among the Kzinti were engaged in war and killed, so they didn't reproduce. So, quickly over time, we have evolution in action and the remaining Kzinti males are less violent. This actually saved the Kzinti race because, likely, other species would have wiped them out due to the Kzinti's violent ways. This explains it:

https://en.wikipedia.org/wiki/Kzin#The_Man-Kzin_Wars

So, in a nutshell, the Neolithic Revolution led to a stratification of males and disproportionate male deaths compared to female deaths, especially for young males who then don't reproduce.

NathanDavis · Accepted Answer

this guy... right here

Agape93 · Accepted Answer

Because in human history, in most societies, women had no say in the matter. Those who could provide or rape, could pass along their genes. Women couldn't take contraceptives really, couldn't say no and have it mean anything, and couldn't abort it.

Kelly6 · Accepted Answer

@kelley1 it is true because 1 man can impregnate 100 women once a year  But 1 woman can only get pregnant once a year.

Hardon-Collider · Answer

Let's go back to cannibalism too. It's natural.

MontBlanc · Answer

From what I’ve read, it’s because in the past a smaller number of men had children with multiple women, while a lot of men died in wars or never had the status or stability to start a family. Most women still ended up having kids because that was just how societies were set up.

Today it’s less extreme, but slightly more women than men still have children. Some men delay it, some don’t want it, some just never settle down. Now it’s more about choice and life situation than survival or status.

Nik1hil · Answer

Men Fall sick and Die too quick.

Testosterone Increases Musculature but it also Is Immunity suppressant!.. More Testosterone can Shut down Immune System of a man and Even flu or Common Cold can Kill him!..

Women are Resilient, Disease cannot kill them and Their Hormones make them Naturally Beautiful, as Puberty Hits them.

Also If there is Scarcity if Food, Women become thinner and Sexier, but if there is sudden Food scarcity men end up Losing Muscles and becoming weaker.. 😅

So Yeah, That's why Nature is Called mother..

Also, Men are weak, One Kick to the Balls and, we curl up to Ground!

jshm2 · Answer

It's dubious numbers at best. So don't look too much into it.

As for possible reasons, then 99% of people killed in wars, are men, 99% of people captured/raped in wars are women. Some women can produce twins, triplets and more.

Also women live twice as long as men. So she could have married and birthed children from two (or more) different men.

Hence why I said it's dubious numbers at best. Population recordkeeping was not as big a thing as it is now.

a_gallant_one · Answer

Could be because women are extra picky about their partners, and they all women actually want womanizers, who are adored by many women. And most of the time it has little to do with looks, money, or any other qualities, the most important thing to them is status, because women are beautiful, but vain creatures, and most of them love only themselves, and the only thing that matters in their life is being better than other girls, making them feel envious, having a partner they can vrag about. There are girls who are both good and beautiful, but it doesn't mean they don't like high status womanizers, they do. Girls can hate me for telling the truth, but it is what it is, and many intelligent people throughout history have written many things on this subject, even those adored by many beautiful women.

Tarifa · Answer

Primitive societies meant that men would either hunt for food or get involved in tribal slashes and warfare. I would think that life expectancy of the male population, in general, hardly ever got beyond 30 years.

It's probable that monogamy was not the standard as it is today.

Hagar88 · Answer

Makes sense. Throughout history a lot of women died in childbirth. Child birthing was risky for a woman in the past. So a man on a postion to marry would take another wife I his wife died in child birth. Having children in the past was important, you wouldn't marry your daughter to a man who couldn't take care of her and her kids. Having large families was important for a man's success.

HighValue · Answer

That doesn't take into account the many men that died at an early age due to wars. Wars have always been a large contributing factor why many men never got to reproduce. Even in modern history, in the two world wars, it was mostly young men in their early to mid 20s fighting and dying before they even had a chance to live much of their lives.

MrChinaski · Answer

The purpose of 'monogamous marriage' as concocted by all male theocrats thousands of years ago was to deprive women of the choice to breed with the strongest male in order to ensure there was a supply of women to share around between the men. This tended to quell violent feuds within the tribe, allowing them to better focus on violently feuding with rival tribes.

RavVid · Answer

There are only 10 ancestral fathers in Europe cause the girls liked early neolithic farming men about 10,000 years ago.

For myself I don't want child support payments, so don't look for me to knock you up. :)

AviatorTom · Answer

For every pair of men and women, there are 3 X chromosomes and 1 Y chromosome. Makes sense that science would find more women reproducing than men.

DryGermanGuy · Answer

I’m pretty sure these statistics also include the women doing so… involuntarily (war, revolution, slavery…), if you know what I mean?

DextroShade · Answer

A lot of men died in war versus almost none of the women

Mike_Hum · Answer

Probably because Men have been in wars and also do more dangerous work.

LiamS95 · Answer

Welll, men cannot actually reproduce we can only assist with the process.

katiesmuff · Answer

I can see where that could be very probable and Kelly 1 explained exactly the reason.

aceleon · Answer

umm maybe because the desired gender is female in every species of life out there.

Dargil · Answer

Which of those women reproduced without the help of men?

AgentG111 · Answer

Um W T actual F?  Only the female human can reproduce!  You seriously are an incredible person!

jamesgoldman · Answer

Because many men were kept as slaves but often leave unwanted daughters to perish as babies

beefcakebradybatson · Answer

Maybe to ensure a handsome black cowboy was born !!!

msc545 · Answer

How women and men reproduce because women have sex with more men than men have with women.

FreyaRed · Answer

Men aren't pregnant

Miristheiss · Answer

Sounds about right.

Throughout human history, 40% of men have reproduced compared to 89% of women. Why was that, and is it still true that more women than men reproduce?

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What Girls & Guys Said

Why does there seem to be way more single men than single women nowadays if the ratio between the sexes are still nearly equal?

Throughout human history, 40% of men have reproduced compared to 89% of women. Why was that, and is it still true that more women than men reproduce?

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What Girls & Guys Said

Why does there seem to be way more single men than single women nowadays if the ratio between the sexes are still nearly equal?

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