Are we all related? This compares the number of ancestors required to produce a person born in the year 2000 against the estimated world population for given years, going back to 10,000 BC. The number of required ancestors in 10,000 BC is a number without a name, such as billion, trillion, etc. We all have exactly two parents, four grandparents, eight g-grandparents, right? In other words, for a person born in the year 2000, there would have been 8,192 living souls in the year 1640 who were direct ancestors of that person. In 1610, there were 16,384 living souls who were direct ancestors. In the year 1430, there were over a million direct ancestors. Click here for chart.