2 reasons why mothers far outnumbered fathers in human history

Surprising studies revealed why mothers affected the genetic pool more than fathers.

  • Studies showed that in human history, mothers often outnumbered fathers.
  • This happened because of polygyny and migration patterns.
  • Modern ratio of mothers to fathers is closer to 1 to 1.

In the course of human history, have there been more mothers or fathers? By the basic logic of it, there should be as many of one as the other. But there's nothing basic about about how humans procreate, pulling their kind forward through the eons by hook or crook. It turns out, there have been significantly more mothers than fathers. A profound fact to ponder as Mother's Day comes around. Women have made a much larger genetic contribution to the world's population than men.

Certainly now the ratio is much more equal but over time it was often not so. A fascinating DNA study in 2014 found that polygyny, the practice of one man having many wives, was partially responsible for why moms outnumber dads if you look at the human population growth as a whole. Another big reason - migration patterns which often had wives leaving their towns to move in with their husbands, making females travel more. This practice would, in turn, widely spread female mitochondrial DNA, while lowering genetic variation among populations.

Study researcher Mark Stoneking, a professor of biological anthropology at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, attributed historical practices of human societies the responsibility for the phenomenon.

"Imagine a population of 100 females and 100 males," said Stoneking to the Guardian. "If all the females but only one of the males reproduced, then while the males and females contribute 50:50 to the next generation, the male contribution is all from just one male."

His team's genetic analysis looked to compare the paternally-inherited Y chromosome with maternally inherited mitochondrial DNA in samples from 623 males from 51 different populations around the world. This allowed the researchers to paint an interesting picture of human genetic migrations.

The patterns weren't the same geographically – there were stronger genetic differences for paternal than for maternal DNA in people from East Asia and Europe, pointing to higher levels of female migration. In populations from the Americas, Oceania and Africa, larger differences for maternal DNA than for paternal were found, suggesting that fewer males reproduced.

You can check out their study in Investigative Genetics.

In another proof of the effects of polygyny on human genetics, a 2015 study found that about 8,000 years ago, 17 women were reproducing for every one man. How could that happen? "It wasn't like there was a mass death of males," explained Melissa Wilson Sayres, a computational biologist at Arizona State University who was involved in that study.

According to Dr. Toomas Kivisild, a biological anthropologist on the team, the reason for the discrepancy lies in periods of human history when few men were able to accumulate so much wealth and power that they would essentially be able to prevent other less successful men from reproducing. And this wealth and power would be passed on to the sons of these men, ensuring the continual survival of their genetic lineage.

Why ‘mom guilt’ is an unreasonable term

Should you defend the free speech rights of neo-Nazis?

Former president of the ACLU Nadine Strossen discusses whether our society should always defend free speech rights, even for groups who would oppose such rights.

Sponsored by Charles Koch Foundation
  • Former ACLU president Nadine Strossen understands that protecting free speech rights isn't always a straightforward proposition.
  • In this video, Strossen describes the reasoning behind why the ACLU defended the free speech rights of neo-Nazis in Skokie, Illinois, 1977.
  • The opinions expressed in this video do not necessarily reflect the views of the Charles Koch Foundation, which encourages the expression of diverse viewpoints within a culture of civil discourse and mutual respect.
Keep reading Show less

Harness the Power of Calm

Tap into the "Rest and Digest" System to Achieve Your Goals

Big Think Edge
  • In the fast-paced workplaces and productivity-focused societies many of us inhabit today, it is easy to burnout.
  • Emma Seppälä, a Stanford researcher on human happiness, recommends tapping into the parasympathetic nervous system instead—"rest and digest"rather than "fight or flight."
  • Aiming for energy management rather than time management will give you the resilience you need to excel at the things that really matter in your life and career, rather than living "mostly off" by attempting to seem "always on."

Apple co-founder says we should all ditch Facebook — permanently

Steve Wozniak doesn't know if his phone is listening, but he's minimizing risks.

Photo by Bryan Steffy/Getty Images
Technology & Innovation
  • Steve Wozniak didn't hold back his feelings about the social media giant when stopped at an airport.
  • The Apple co-founder admitted that devices spying on his conversations is worrisome.
  • Wozniak deleted his Facebook account last year, recommending that "most people" should do the same.
Keep reading Show less

Where the evidence of fake news is really hiding

When it comes to sniffing out whether a source is credible or not, even journalists can sometimes take the wrong approach.

Sponsored by Charles Koch Foundation
  • We all think that we're competent consumers of news media, but the research shows that even journalists struggle with identifying fact from fiction.
  • When judging whether a piece of media is true or not, most of us focus too much on the source itself. Knowledge has a context, and it's important to look at that context when trying to validate a source.
  • The opinions expressed in this video do not necessarily reflect the views of the Charles Koch Foundation, which encourages the expression of diverse viewpoints within a culture of civil discourse and mutual respect.
Keep reading Show less