A researcher in Denmark has concluded that every blue-eyed person in the world is related.

Evidence suggests that every human being that existed up until around 6,000 or 10,000 years ago had brown eyes. DNA testing helped reveal that it was a mutation that occurred thousands of years ago that caused some people to have blue eyes. This certainly must have been a startling development for the people of the time who had only ever seen people with brown eyes up until that point. People with blue eyes are quite likely to be descendants of that first blue-eyed individual, according to Factual Facts.