Ancestral mathematics

In order to be born, we have to have needed:

 2 Parents

 4 Grandparents

 8 Great-grandparents

 16 Great-grandparents

 32 

 64 Pentagrandparents

 128 Hexa-grandparents

 256 Hepta-grandparents

 512 Octa-grandparents

 1,024 

 2,048