In order to be born you needed: 2 parents, 4 grandparents 8 great-grandparents 16 second great-grandparents 32 third great-grandparents 64 fourth great-grandparents 128 fifth great-grandparents 256 sixth great-grandparents 512 seventh great-grandparents 1024 eighth great-grandparents 2048 ninth great-grandparents For you to be born today from 12 previous generations you needed a total of 4094 ancestors over the last 400 years.