Social media is currently popularizing "people who look like me" content, where faces found via Google image search are cropped and used as stickers in videos, often showing celebrities at the end. This trend is especially popular on Instagram and TikTok and is widely embraced by many influencers.
Although it sounds like fun on social media, the idea that there must be someone in the world who looks like us has long been studied. This idea is known as the Doppelgänger Theory, which proposes that there are about 7-11 people on Earth who look like us, with roughly a 9 percent chance of encountering someone who resembles us without any blood relation.
Seeing is believing, so François Brunelle, a Canadian photographer from Montreal, started a project called “I’m not a Look-Alike” in 1999. The project’s goal was to invite people who look alike but are unrelated to have their photos taken together. His inspiration was simple: someone once told him he resembled Mr. Bean, or Rowan Atkinson, and he thought it would be fun to find others with similar experiences.
However, the hardest part was finding look-alikes. Initially, Brunelle searched locally by walking around his city, but after finding only 8-9 pairs, he realized he needed a larger network. He contacted media to spread the project online and created a website to receive messages from around the world. Brunelle received thousands of messages, including pairs who already knew each other and referrals. Ultimately, he found 250 unrelated look-alike pairs from 32 cities, contacted them, and traveled across countries to photograph them.
In these paired photos—some of people who knew each other and others who didn’t—the resemblance is striking, almost like twins born to the same mother, with similarity levels between 70 and 90 percent. Brunelle’s “I’m not a Look-Alike” project opened opportunities for further studies, especially by scientists. While the Doppelgänger theory had been mostly theoretical, Josep Carreras, a geneticist from Spain’s Leukemia Research Institute, contacted Brunelle after seeing the project. Carreras studied the genetics of 32 pairs and found that 16 pairs shared such similar genes they could be considered true twins.
Moreover, the study found these look-alikes not only resembled each other physically but also shared similar lifestyles, heights, education levels, weights, and even smoking habits. One remarkable pair of women not only looked like twins but also shared the same birthday, lived in the same apartment, and had tattoos from the same tattoo shop.
How is the Doppelgänger theory possible, and how can it be explained biologically?
The term “doppelgänger” comes from German meaning "double walker." It first appeared in a 1796 novel by German writer Jean Paul. At that time, genetics was unknown, so the origin of doppelgängers was linked to magic and supernatural beliefs.
Western folklore tells that encountering someone who looks identical brings disaster, and if family or friends meet a look-alike, misfortune or illness will soon follow.
In contrast, the existence of look-alikes is not magic but due to limitations in human genes—or simply put, "there is a limited range of human facial patterns." The genome is like a deck of cards shuffled into many combinations, but even so, the deck contains a fixed number of cards. Mathematically, someone looking like another is akin to shuffling a deck many times until similar genetic patterns emerge. Because the world population is so large, the chances, though small, do exist. The extent of similarity depends on how many facial features match, which correlates with genetic similarity, even across different races. Scientists have tested look-alikes for similarity across eight facial regions, estimating the occurrence at about one in a trillion.
This is the wonder and coincidence of biology that can actually be observed. Of course, the chance of meeting someone who looks exactly like us is not easy since everyone has a different number of doppelgängers, depending on how the genetic "deck" is shuffled at each birth.
Yet, with a global population of about 8.3 billion, it’s reasonable to wonder if there is at least one person who looks like us somewhere on Earth. Perhaps when we step out to buy food at the street corner, we might see another version of ourselves standing there as well.
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