Every person on Earth is a distant cousin to everyone else

Science · Published 26 October 2026 Swipe more like this →

In short: If you trace your family tree back just 33 generations, the math becomes overwhelming. You would have over eight billion ancestral slots to fill—more people than are currently alive on the planet. This means our family trees aren't just branching out; they are collapsing into one another.

Humanity is far more interconnected than our cultural psychology leads us to believe. Because the number of ancestors grows exponentially with each generation—doubling every step back—the 'slots' in a family tree quickly exceed the total human population. By the time we reach roughly 800 to 1,000 years ago, the sheer number of forebears required to produce the current population means that almost everyone with common ancestry is related to everyone else. This exponential growth makes it impossible to focus on just one branch without ignoring the others. Genealogists are limited by this fact because they can only track one lineage at a time. The math proves that our family trees are not just large; they are mathematically impossible to keep separate.

Due to its widespread nature, geneticists observe that individuals of European descent are all direct descendants of Charlemagne. We are often conditioned to think of ancestry in narrow, linear terms, but the reality is a dense web of shared lineage. Genetic data in the 21st century has begun to confirm that we are all descended from a common human mother, illustrating a level of kinship that spans the entire species. This concept is known as a genetic isopoint. It highlights how we are psychologically conditioned to ignore these broad connections. We often prefer to see ourselves as isolated individuals rather than members of a massive, shared human web.

This interconnectedness extends beyond our own species. All life on Earth shares a fundamental blueprint: DNA. While the sequence of these molecules determines the difference between a human and a tomato, the underlying chemistry is the same. Every living thing, from plants to animals, traces its lineage back to a single common ancestor—LUCA (Last Universal Common Ancestor)—which lived approximately 3 to 4 billion years ago as a single-celled organism. Humans share about 99% of their DNA with chimpanzees and 97% with orangutans. We also share 60% of our DNA with mushrooms. This means that eating a mushroom is biologically closer to eating chicken than it is to eating a salad.

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