The following is from the Reader's Digest (date/issue unknown).
Next time you're feeling rather unimportant, try a little arithmetic trick base on the unbeatable fact that it took two people, your parents, to get you here. Each of your parents has two parents, so in the generation just prior to that or your mother and father, there were four people whose pairing off and sharing love contributed to your existence.
You are the product of eight great-grandparents, 16 great-great-grandparents, 32 great-great-great-grandparents, etc., Keep multiplying the number by two. If you figure an average of about 25 years between each generation, you'll discover that a scant 500 years ago, there were 1,048,576 people on this planet beginning the production of you.