Imagine a future where the unthinkable happens. A global catastrophe wipes out nearly everyone on Earth, leaving only two human beings alive. With the survival of the species now resting on their shoulders, the question becomes: could two people really repopulate the world?While it sounds like the ultimate test of resilience, rebuilding humanity from just two individuals would come with serious biological and societal consequences. Here are six key things that would happen if the fate of the world depended on just two survivors.1. Inbreeding Would Be UnavoidableIf only two people were left to restart humanity, future generations would be forced to reproduce within an extremely limited genetic pool. Over time, their children would have to pair with siblings, cousins, or other close relatives in order to keep the population going.Although modern society views inbreeding as deeply taboo, it has occurred throughout human history, especially during moments of survival or in royal bloodlines aiming to preserve power. But this kind of reproduction carries serious consequences. With each generation, the risk of genetic disorders, birth defects, and weakened immune systems would increase, threatening the long term health and stability of the population.2. Genetic Disorders Would Become More CommonEach person carries between five and ten harmful recessive genes hidden in their DNA. In a large and genetically diverse population, these genes usually remain unnoticed because they are unlikely to match up. But in a small, isolated group where people are closely related, the chances of these dangerous genes pairing together rise significantly.As generations pass, the children of relatives would be more likely to inherit serious genetic disorders. These could lead to shorter lifespans, developmental issues, physical or cognitive disabilities, and problems with reproduction, making it harder for the group to survive long term.3. There Would Be No Genetic DiversityGenetic diversity plays a critical role in keeping species healthy and adaptable. It allows populations to resist diseases, adjust to environmental shifts, and maintain strong, functional genetics across generations. But if only two humans were left to restart civilization, all of that diversity would disappear. Their children would share nearly identical DNA, resulting in a population highly susceptible to genetic disorders, weakened immune systems, and limited ability to adapt or evolve in the future.4. History Suggests It Could Be PossibleAround 70,000 years ago, a powerful supervolcano eruption may have pushed humanity to the brink of extinction, shrinking the global population to just a few thousand people.Some scientists believe that a limited amount of inbreeding during this time helped ensure our survival, even though it came with genetic risks. In more recent history, royal families like the Habsburgs practiced inbreeding to maintain pure bloodlines. However, this strategy backfired, causing serious genetic disorders and playing a role in the collapse of their dynasties.5. The Neanderthals Might Offer a WarningNeanderthals, our closest ancient relatives, likely went extinct in part due to intense inbreeding among small, isolated groups. Their limited gene pool made it difficult for them to adapt, leaving them more vulnerable to disease, environmental shifts, and reproductive issues. If modern humans had to rebuild society starting with only two individuals, we might face the same genetic challenges that ultimately helped drive Neanderthals to extinction.6. The Odds of Survival Would Be a Roll of the DiceIn the end, repopulating the Earth with just two people would be a game of genetic chance. Some offspring might be healthy, while others could suffer severe consequences. Without modern medicine or technology to intervene, survival would hinge entirely on luck and the slow hope that evolution might eventually introduce enough variation for humanity to thrive again.So, while two people might be able to spark the rebirth of civilization, it would come with risks that no one can fully control. In a world without diversity, survival itself becomes the greatest challenge.