If you go back 25 generations, you have 33,554,432 ancestors.

Assuming no inbreeding occurred in the past 25 generations, you should have 33,554,432 great great great great great great great great great great great great great great great great great great great great great great great grandparents. If you added together ALL of your potential ancestors (including your parents, grandparents, great grandparents, great great grandparents, etc.) you really have a total of 67,108,862 ancestors. Of course, this is only true IF none of your ancestors ever had children with any of their relatives (not even 23rd cousins!), which in the course of 25 generations is a huge “if”.



Feel free to check the math:



2^25=33,554,432



2^25+2^24+2^23+2^22+2^21+2^20+2^19+2^18+2^17+2^16+2^15+2^14+2^13+2^12+2^11+2^10+2^9+2^8+2^7+2^6+2^5+2^4+2^3+2^2+2=67,108,862