Who had the most kids in history? Or, humanity's near-extinction and why it matters for us all.

A new study about population bottlenecks raises fascinating questions about the individuals who most shaped our species in the past—and those in the present day who are most making their genetic mark.

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The news is bleak, so let’s Zoom out, and look elsewhere to find something a bit uplifting and unusual in an unexpected place.

When we speak about individuals who changed history, we tend to think of leaders, innovators, and those who swayed the trajectory of human events. But those consequential figures only changed what people did.

What about the individuals who most changed who we are?

Every human trait has an absolute maximum. There’s the tallest person who ever lived, the strongest, and so on. Someone, known or unknown, had the most back hair or the smallest nostrils or the heaviest spleen, of any human, ever.

But that also means that there is precisely one person, throughout the long stretch of human history, who has most affected the future genetic path of our species.

Who was it? And why does it matter? The answers, which may lie in a striking new revelation about the near-extinction of our ancestors, raises jarring questions about our collective existence—and teaches us an important lesson about our species.

History’s Most Prolific Parents

Let’s start with an easier question: who gave birth to the most children in history?

Between 1725 and 1765, Valentina Vassilyev was apparently rather busy. According to a local monastery’s records, the prolific Russian mother “popped out 16 pairs of twins, seven sets of triplets and four sets of quadruplets, over 27 separate labours. The grand total: 69 children.” If true, this would make her the record holder.

Thankfully for Valentina, this was probably not true, partly because it would mean she had survived 27 childbirths in the 18th century—when even one childbirth was dangerous for the mother—and partly because it’s unlikely that she would have been fertile for forty years straight, as was claimed.

Tall tales aside, the extremes of human childbearing are nonetheless astonishing. (The verified record holder for most births is a Ugandan mother named Mariam Nabatanzi, who has a rare genetic condition called hyperovulation, and gave birth to 44 children across 15 births from 1993 to 2016. Spare a thought for her, as she is a single mother to her 38 surviving kids).

For men, the numbers are off the charts. While records are difficult to confirm, it probably is true that Genghis Khan has fathered the most children in history, as estimates range between 1,000 and 3,000 direct offspring from his enormous harem. A 2003 study estimated that 16 million men alive today are direct descendants of Genghis Khan. (Similar studies have shown a Y-chromosome lineage linked to at least ten other extraordinarily prolific dads, including the Qing Dynasty ruler Giocangga).

But modern technology has created fresh possibilities for passing on your genetic line. You no longer need to be a brutal, murderous ruler to father hundreds of children.

Take Bertold Wiesner, for example. You may have never heard of him, but he coined the term “Psi” to refer to alleged parapsychological phenomena like extra-sensory perception. In the realm of scientific reality, his research helped develop innovations in pregnancy tests and oral contraception. This was somewhat ironic, as a man who played a major role in helping women avoid unwanted pregnancies is near the top of the human league table in terms of fathering the most children.

With his wife, they founded a fertility clinic in 1940s London, which worked in the (then controversial) project of artificial insemination. Wiesner was the sperm donor for about 40 percent of the 1,500 pregnancies facilitated by the clinic, making him the father of an estimated 600 children.

The Dutch Lion and the Hidden Perils of Swiping Right

More recently, a court case in the Netherlands exposed an alarming fact: that a Dutch musician in his early 40’s named Jonathan Jacob Meijer had fathered between 550 and 600 children through sperm donation. Meijer is a bit of a Dutch lion, with “a mane of curly blond hair.” In online ads promoting his suitability as a sperm donor, Meijer has described himself as a “musical Viking donor.”

Plenty of women have been drawn to that profile, not just in the Netherlands, but in Ukraine, Argentina, Australia, and beyond. (Some estimates put the number of Meijer’s children as high as 1,000, a figure he denies). This prolific fatherhood has created some disturbing risks, that half siblings may, by unfortunate accident, not know that they are related and end up having their own children together. That may sound like a remote possibility, but there are only 17 million people in the Netherlands, so it’s a serious concern.

In a separate case, a different Dutch sperm donor fathered over 200 children. This has led to half-siblings nearly getting together. According to The New York Times, “one half brother, Jordy Willekens, who lives in The Hague, matched on an online dating app with four half sisters. ‘Once, I swiped on a sister and she swiped right on me at the same time,’ Mr. Willekens said.”

If Meijer’s YouTube channel is anything to go by, it is a shame for humanity that he is going to have such a disproportionate impact on the future Dutch population, given the titles of his videos: “Labradorite: my new gemstone”; “The power of the mountain crystal”; “How to get rid of WOKE”; and “Evil dentists - how they destroy your teeth.”¹

One of his videos is titled “I do NOT believe in evolution.” But evolution is real, and Meijer is likely to have more impact than 99.99 percent of people on humanity’s future gene pool. However, even if he has fathered 1,000 children, it’s thankfully still a drop in the bucket of billions: 1,000 out of 8 billion isn’t that much. In that fraction, the numerator is a large number, but the denominator is so enormous that Meijer isn’t a strong candidate for someone who’s most going to affect the future of humanity.

So, to find the person who most affected the genetic development of modern humans, we need to go into the distant past, and, with new research, think about times in which the denominator—the total number of humans alive—shrunk to an alarmingly tiny number. Because, if the new study is correct, we all very nearly did not exist.

The Scientific Adam and Eve

The origin story of our species remains shrouded in mystery, but this much is clear: we are bipedal Great Apes in the Hominid family and our distant ancestors, at some point, evolved to became more like us.

There’s considerable debate among evolutionary biologists, not just about who the first humans were—but also over what we mean when we say “human.” (If you want to start a long discussion, ask a room full of evolutionary biologists to define the word “species.” There are several dozen definitions competing for dominance in the field).

Nonetheless, at some point, an evolutionary branch split, and the offshoots of that branch gave rise to us, making that early group of human-like hominins the common ancestor for everyone from Genghis Khan to Madonna. These ancient people are particularly interesting, because they shaped all of human history.

But did humans ever have a true Adam and Eve moment, in which there were just two of us, a universal common ancestor we can all trace back as our distant genetic relatives? (The answer is likely no; evolutionary history is not quite so neat). But as we’ll see, when there were only small numbers of our ancestors alive—when the human denominator was small—it matters a hell of a lot what they were like.

Population Bottlenecks and Lessons from the Cheetah

11,000 years ago, cheetahs almost went extinct. Evidence suggests that, in the entire world, there were as few as seven cheetahs alive. This is an example of a population bottleneck, in which the population of a species drastically shrinks, often due to environmental change or a cataclysmic event that wipes most individuals out.

The cheetahs had such an extreme population bottleneck that all modern cheetahs are extremely similar genetically—so much so that you can take skin from any cheetah and graft it onto another. The host animal’s body will immediately accept it as though the other cheetah’s skin is its own.

Now, consider this: how much would it matter which seven cheetahs survived? If even one of them was unusually slow, or had an extremely bushy tail, or had an unusual genetic mutation, well, that would dramatically influence the future trajectory of the species.

Similarly, if we imagine that the entirety of humanity were suddenly restricted to just seven people, I think you’d agree that the future of Homo sapiens would be rather different if one of those seven was, say, Donald Trump or Elon Musk rather than a compassionate, selfless nurse who works on a ward for children with cancer.

Population bottlenecks drastically amplify the importance of any individual within the genetic pool. Every individual that produces offspring during a bottleneck is likely to have an outsized influence on the future of the species.

New Research on the Near-Extinction of Our Ancestors

According to a new paper by Chinese researchers published in Science, one of the top research journals in the world, the precursors to humanity nearly went extinct roughly 930,000 years ago. Before that time, they suggest, there were about 98,000 human ancestors who were producing children, across the whole planet. Then, something—likely abrupt climate change—caused those numbers to plummet.

Soon, they estimate, there were fewer than 1,280 breeding individuals alive, tiny numbers that stayed low for 100,000 years. This hypothesis also neatly explains why there is such a gap in the fossil record of human ancestors from this time period; the researchers suggest that it may just be because there weren’t that many people to leave fossils behind.

If correct, this would be an astonishing revelation, because it would mean that 98.7 percent of human ancestors were once wiped out, a cataclysmic event that both reduced the genetic diversity of our forefathers, but also one that made it really matter which 1,280 human ancestors survived.

And, most likely, the survivors were somewhat arbitrary and accidental, a pivot moment that forever changed humanity, but without much rhyme or reason to it. It may have been an instance of both survival of the fittest, but also survival of the luckiest—our ancestors were those who just happened to be in the right place at the right time when their environment turned inhospitable.

The evidence remains speculative, and many scientists have questioned these claims, but it is clear that human bottlenecks have existed at various points in our history. One contested theory, about the eruption 70,000 years ago of the Toba supervolcano (in modern day Indonesia), suggests that the eruption wiped out all but a few thousand humans. Several other bottlenecks and founder events have been suggested and verified. (Let us hope that no similar cataclysmic event is triggered by modern climate change).

So, absent a scientific Adam and Eve, it’s likely that the humans who most affected the trajectory of our species—and shaped the way that all of us are today—are those people who happened to survive a drastic shrinking of humanity’s gene pool.

Thankfully, even the most prolific fathers today—like Meijer, the anti-science Dutch Lion—will only sway a tiny proportion of the future gene pool, whereas each child that emerged from a total human population of 1,280 survivors in the distant past would matter enormously to our current collective identity.

This way of thinking also reveals a profoundly beautiful insight: because of population bottlenecks, humans are all really similar to one another. Take two of the most different seeming people from the most distant regions of the planet and they’re likely to be more genetically similar than two chimpanzees living on opposite sides of one river in Cameroon.

We may be divided by racism, by cultural wedges, by persistent hatreds. We love to hate “the other.” But compared to similar species, our genetic similarity yields a moving biological truth that we must all remember:

Hating other humans is astonishingly akin to hating ourselves.

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Thank you for reading The Garden of Forking Paths. If you’ve found this article interesting, or learned something new and would like to support my research and writing, please consider upgrading to a paid subscription. Truly, as this article makes clear: every person matters.

1. (I’m, of course, being tongue-in-cheek here, because even though he will have a disproportionate impact on the human genome in the broad sense, personalities, beliefs, and behavior are only partly linked to genetics — significant swaths of variation in humanity are akin to developmental dark matter, where we don’t understand it, and yet variation happens enormously through culture, context, upbringing, lived experience, etc).