Oh we have a debate going. Good, I need something to do on this boring 4 1/2 hour plane fight to Baltimore.  What, no WiFi and no food? I may be late to the debate. Oh well. So now I will have to explain the fuzzy math that led me to believe that the 3rd and 4th cousins are being way over-called at both 23andMe and FTDNA. I specifically was discussing 3rd cousins because there is much more of a likelihood of actually matching a paper trail with one or more of them on a segment, and it is also harder for others to question the statistics if I am slightly off. At first I was figuring everybody only doubles themselves every generation but that may not be realistic, so let me re-figure the calculations as follows. Lets assume every couple has 4 children and every single one of those lives to have 4 more children. Maybe your ancestors had more than this, but some probably did not live to have large numbers of descendants. Most of today's families are not even this large. So the figures can vary quite a bit depending on the situation. Mormons may have more than Eastern European Holocaust survivors, for example. If there is no pedigree collapse, how many great-great grandparents do each of us have? Then figure how many great-great grandchildren these ancestors would have had. I am not counting people like Mitt Romney whose great-grandfather was a polygamist. My husband is editing this message as I am writing it BTW and putting his two cents worth in…He doesn't  do much math or genealogy but he can sure tell me about key political figures. 2 X 2 X 2 X 2 = 16 great-great grandparents How many mating couples = 8 in that particular generation Suppose each of the original 8 couples had four children per couple = 32 children 32 each have 4 = 128 grand children 128 each have 4 = 512 great grand children 512 each have 4 = 2048 great-great grand children Then you need to subtract yourself and your sibs from that number which is insignificant to calculate 3rd cousins. So I guess that comes out to be about 6.5 in a million chance of testing a third cousin instead of one in a million Americans that I estimated previously. I am assuming that many people who do genealogy are Americans also have a lot of Colonial ancestors so the majority might fit this scenario. I can't do the math unless I have a total finite potential number of testing individuals, so 313,000,000 potential testees seems reasonable. If you want to use the entire world population as potential testees, then be my guest. It only further supports my point. Maybe if a lot of your cousins are overseas the one in a million is not so far-fetched.  On the other hand, maybe you have a 1 in 100,000 chance. However, FTDNA has not tested over 100,000 for FF, have they? I might believe their predictions if they had. I figure a lot of those predicted 3rd and 4th cousins are actually 5th or greater cousins that just happened to have larger than predicted segment sizes. That goes for 23andMe as well. Yes, 23andMe has over 100,000 people in their database but how accurate are their predictions? How many times do you get a message in your Inbox from So-and-so, "a third cousin" or from " So-and-so a fourth cousin"? Don't these seems a little unrealistic? The closer ones you want to hear from don't often answer your e-mails. Well, while I am in a calculating mood, lets figure 4th cousins the same way and see how the odds change. 16 mating couples have 4 children = 64 64 children have 4 children = 256 256 grandchildren have 4 children = 1024 1024 great-grandchildren  have 4 children = 4096 4096 great-great grandchildren = 16,384 great-great-great grandchildren which translates into 5.2 in 100,000 chance of testing a 4th cousin in a finite American population of about 313,000,000.;ll6 Now for 32 mating couples 32 couples each have 4 = 128 children 128 each have 4 = 512 grandchildren 552 each have 4 = 2048 great grandchildren 2048 each have 4 = 8192 great-great grandchildren 8192 each have 4 = 32768 great-great-great grandchildren 32768 great-great-great grandchildren have 4 = 131,072 gt-gt-gt-gt grandchildren which translates into 4.2 in 10,000 chance of finding a 5th cousin. It appears 5th cousins are much more likely to test than 3rd and 4th cousins. Now for 64 mating couples 64 couples have 4 children = 256 256 children have 4 = 1024 1024 grandchildren  have 4 children = 4096 4096 great-grandchildren have 4 =  16,384 great-great grandchildren 16,384 great-great grandchildren have 4 =  65,536 gt-gt-gt grandchildren 65,536 gt-gt-gt grandchildren have 4  = 262,144 gt-gt-gt-gt grandchildren 262,144 gt-gt-gt-gt grandchildren have 4 = 1,048,576 gt-gt-gt-gt-gt grandchildren which translates into a 3.4 in 1,000 chance of testing a sixth cousin randomly. Beyond that I would think that pedigree collapse would considerably change the figures. Having more or fewer children would also change the numbers a lot. Nevertheless, there is a big difference in the number of your 3rd cousins versus the number of your sixth cousins who are likely to test at random, regardless of whether they match you on your DNA or not, and regardless of the total potential population size. Kathy J.