Ancestor calculation- Can this be right?

Question

As i begin counting the number of people that I am direct desendants of the results are staggering and I soon reach a number which is greater than the number of humans that have ever lived. Example: It took 2 parents to make me, 2 to make each of them, and so on and so on...represented

2 to the 30th power(30 generations back)= >1Billion
30 generations before that=>1Billion sets of 1Billion
30 generations before that=>1billion sets of 1 Billion sets of 1Billion
...one could continue 30 generations at a time and pass the number of humans that have ever been on the planet.(Note the number calculated is not all my ancestors but just that generation's count....adding the generations together creates really huge numbers of direct ancestors that doesn't seem possible)

How can this be?

Answer 1

By the time you go back 6 generations, it is almost certain that you are counting a few ancestors twice, because fourth cousins got married to each other. The further back you go, the more and more likely it gets that at least one of the parents of one ancestor was the parent of some other one, too, so your doubling factor with each generation is wrong.

For a modern and frequently-referred to example, the Queen and Prince Philip are third cousins. Philip's great-grandmother Princess Alice was Queen Victoria's third child, while one of Queen Elizabeth's great-grandfathers was King Edward VII, Queen Victoria's first child. So Prince Charles has one less great-great-great-grandparent than mathematically he could have, because he can't count Queen Victoria twice. Actually, because intermarriage between second and third cousins is so much commoner in Royal families, he may well be four or five short of having thirty-two distinct great-great-great-grandparents.

Answer 2

When my son went to the local junior college, his history professor wanted each student to do a project. My son (well, with my persuasion) decided to do a genealogy project. Counting my Dad, I can go back only 5 generations before hitting that infamous "blank wall". Well, 4 generations ago, my g-g-grandfather married his first cousin. The librarian really threw a fit! (When I was my son's age, it was still legal, at least in New York State, for a person to marry a first cousin.) I could not understand her attitude; read some history books and you will find a lot of people married second cousins, first cousins...Royalty (since Rome) married uncles, fathers married daughters, brothers married sisters...
As to your numbers,
Generation No. How Many Persons No. Fr. To.

1. 1 1
2. 2 2 - 3
3. 4 4 - 7
4. 8 8 - 15
5. 16 16 - 31
6. 32 32 - 63
7. 64 64 - 127
8. 128 128 - 255
9. 256 256 - 511
10. 512 512 - 1,023
11. 1,024 1,024 - 2,047
12. 2,048 2,048 - 4,095
13. 4,096 4,096 - 8,191
14. 8,192 8,192 - 16,383
15. 16,384 16,384 - 32,767
16. 32,768 32,768 - 65,535
17. 65,536 65,536 - 131,071
18. 131,072 131,072 - 262,143
19. 262,144 262,144 - 524,287
20. 524,288 524,288 - 1,048,575
21. 1,048,576 1,048,576 - 2,097,151
22. 2,097,152 2,097,152 - 4,194,303
23. 4,194,304 4,194,304 - 8,388,607
24. 8,388,608 8,388,608 - 16,777,215
25. 16,777,216 16,777,216 - 33,554,431
26. 33,554,432 33,554,432 - 67,108,863
27. 67,108,864 67,108,864 - 134,217,727
28. 134,217,728 134,217,728 - 268,435,455
29. 268,435,456 268,435,456 - 536,870,911
30. 536,870,912 536,870,912 - 1,073,741,823
31. 1,073,741,824 1,073,741,824 - 2,147,483,647
32. 2,147,483,648 2,147,483,648 - 4,294,967,295
33. 4,294,967,296 4,294,967,296 - 8,589,934,591
34. 8,589,934,592 8,589,934,592 - 16,179,869,183
35. 16,179,869,184 16,179,869,184 - 32,359,738,367
36. 32,359,738,368 32,359,738,368 - 64,719,476,735

Supposing two unrelated persons for each generation (no cousins, what have you), each generation would double. 36 generations ago was the late 800’s on Mom’s Ahnentafel. That was a long time after Adam & Eve !!!

When they say we are all related, they are not kidding. Roughly everyone has a common ancestor within the past 800 - 1000 years. People who pretend to be mortified by insest obviously failed basic math! Hello, cousin!

Answer 3

You are calculating numbers back in time in a ratio of 1:2, that is one of you to two parents, In reality, through most of human history, two parents produced many off-spring (often 10 or more!). So, your backward looking ratios need to reflect this (e.g. 10:2). So, 10 offspring might calculate backwards to 2 parents.