Do you know your second cousins?

Question

This is another of my cousin posts.  Last time I asked how many fourth cousins I was likely to have.  Apparently the only published study gives an answer of 940.  I think that's too low, but proving it is going to be a lot of work. 

So meanwhile I decided to do a little analysis of my closer cousins.  Among other things, I wondered if there was any way to identify a mathematical pattern in the increase by generation (degree of cousinship).  So I began with my first cousins.  I have 16.  I know them all. 

Not getting off to a great start, I then found I have only 12 second cousins.  I am quite sure I have identified them all, but I had to consult my genealogy records to do it, which seems rather pathetic.  Here is this great resource for DNA testing (also a bit pathetic that that's my main interest!).  The reason I have fewer second than first cousins is that my father didn't have any cousins.  I think that is mostly due to the particular circumstances of my family's history.  It seems to me that over the generations, the numbers in the family branches should average out to provide a more normal result, but that remains to be seen. 

Third cousins will be tougher, and more time-consuming, but I'll look at that next.  Update:  I was wrong.  It was easy, thanks to some advice from Nelda (see below)!

Meanwhile, if you have second cousins, I hope you've at least said hello!

Comments

I know/knew all my 21 first cousins (3 are deceased) but I can't say I keep/kept in close contact with them all. I am Facebook friends with all of them who have a Facebook account.

I just tried to count my second cousins. I'm not even sure I have all of them in my database, but the number I have is 127. No, I don't know them all. In fact, I know very few of them.

I have only identified 415 of my 4th cousins. I'm sure there are many I have not identified, but I don't have any idea how many. I have pedigree collapse in my tree on my paternal side so that may have the potential of making my number lower.

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Wow!  127!  

How did you count your fourth cousins?  That is one thing I had intended to ask in a later post.  I don't find any automated means of doing that on Ancestry or in my genealogy software.

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Julie, I use Family Tree Maker and I was able to generate a kinship report which I was able to sort by kinship to me. I still had to do some manual counting of the cousins at each level. I would never have been able to figure it out otherwise.

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Nelda, I have Family Tree Maker, although it's an old version.  I don't use it much.  How do I generate the kinship report?

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I think FTM has always had kinship reports. Mine is FTM 2019. After going to my own page (I'm the "Home Person") I click on the "Publish Button" at the top of the page. The "Kinship" report is in the "Relationship" collection of reports. I then chose each of my GGG-grandfathers and selected all his descendants to be included in the report. (I could have done it without selecting the GGG-grandfathers--just said for it to include everyone in my database--but I would have gotten more results to scroll through than I wanted and it would take longer for the report to generate. As it was, the report was 105 pages!) After I got the report, I selected the option to sort by kinship and counted the cousins at each level of kinship.

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Oh, and regarding the high number of my 2nd cousins, my paternal grandfather was one of 11 children, my paternal grandmother was one of 8 children, my maternal grandfather was one of 11 children, and my maternal grandmother was one of 7 children. That makes for an awful lot of 2nd cousins.

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Nelda, I did find how to generate the kinship report, but it wouldn't save in any other version except .ftm.  It doesn't appear to be sortable.  Any advice?

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My 9-year-old has no siblings or 1st cousins, and it seems likely she will never have any. On my side, she has one second cousin about her age and another two we’ve never met.  

Going the other way, doing the Leeds method with my mother’s DNA is a little weird because she has one set of great grandparents that offered no second cousins. In fact, the parents of the father of that couple offered no third cousins either. The parents of *that* father had only one other line with living descendants, who number three total.

 My wife is from a big family, so they sort of filled up both sides at our wedding!

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Thanks, Barry.  There is sure an interesting range of answers so far.

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I'm sorry, Julie. No advice to make it easier to count. I guess the ability to sort came in later versions than yours. In FTM 19, the report can be exported as PDF, CSV, RTF, and HTML. Maybe someone else would have a better answer for you.

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Nelda, I figured it out!  I found the sort option.  It still wouldn't export in anything but a ftm file, but I used the print option, which has a PDF option within it, and that worked.

I would never have known about the relationship report without your help.  Thank you!  This has saved me hours of work!

By the way, I found it easiest to just run one big report with all the relatives.  Then for third and fourth cousins, I could just count the cousins on the first and last pages of their section, and for all the pages in between just multiply by 57 (the number on each page).

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 Way to go, Julie!

Answer 1

The problem is, when finding cousins of our own generation (1st, 2nd, 3rd, 4th...etc.)... they are mostly still living, so its really difficult to document living people.

As to the mathematical pattern, that would be difficult, as it depends highly on the number of children at each generation, and the number of their children, and so forth. Some families had a dozen or more, while others only two or three or less. You could pick an average number and do some statistical guesswork.

but for example, let's just say each family had only 3 children, and they each had 3 and so on (probably a very low estimate).

Then that would be simple:

• 12 -- 1st cousins ((2 x 3) x 2)
• 72 -- 2nd cousins (((2 x 3) x 3) x 4)
• 432 -- 3rd cousins ((((2 x 3) x 3) x 3) x 8)
• 2592 -- 4th cousins

assuming I've done my math right.
(2 siblings x 3 children) x 2 parents
4 grandparents x 3 more children in that generation
8 great-grandparents x 3 more children in that generation

What really makes the math hard is when cousins marry each other. Or when families have more or fewer children. In my parents and grandparents generations, there were often 8 or more siblings.

Comments

Dennis, I've had pretty good luck with finding living people, often from obituaries.  Or through DNA matches.  But it takes a lot of time, because there are so many lines to trace.

Yes, I have come to believe that there probably isn't a reliable mathematical pattern for any particular family, illustrated by my own example--I have more first cousins than second cousins.  It is not like calculating a person's descendants, because for the cousin calculation, the relevant part of the tree becomes more specific with each generation (I know what I mean, even if I'm not explaining it coherently!).

Then of course the additional problem is that the farther out we go, the harder it is to discover the distant cousins.

However, I'm still determined to show that that estimate of 940 fourth cousins is too low!

Your math above looks OK, I think.  You're showing that each generation increases by six-fold--twice because of the parents added generation and then three times because of the three children in the new generation.  (Right?)

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estimate of 940 fourth cousins is too low

way too low. my example of only using 3 children in each generation shows 2500+ 4th cousins. I suspect a reasonable number should be even higher. Maybe closer to 5000.

No, the math is not linear, its exponential.
https://waitbutwhy.com/2014/01/your-family-past-present-and-future.html

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Very interesting, Dennis.  I haven't read the whole article yet, but I will.  

You may not have seen the previous question I posted where the estimates were discussed:

https://www.wikitree.com/g2g/991292/how-many-fourth-cousins-do-i-have

There were a couple mentions of the Brenna Henn et. al. study that developed the 940 number:

https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0034267&type=printable

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yeah, not really the main point of that paper... but they used 2.5 children per generation, whereas I used 3 in my calculations.

2.5 might be closer for today's generations, but I suspect the number is much higher for older generations, back to a point. And there may be factors involving economics and geographic local that affect those numbers as well.

Their number could be just as valid as my number. There's not an easy way to guesstimate. I think my estimate of 3 children is low, so naturally, I think theirs (2.5) is even lower :)

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I am hoping that we can find some actual data.  I have several ideas of how to do it but have not yet got all my information together.  I'm working on it.

Answer 2

I know all my second cousins on my dad's side, excepting one family that's a lot older and hasn't really kept up. There's only about 16 of them and some are about as close as my 1st cousins. On my mom's side there's something of an over-abundance of second cousins, and I for sure do not know all of them. Both my maternal grandparents were from big families and I think there may be almost 100 great grand children of my two sets of maternal great grandparents combined.

Comments

Good for you!  I see that you're about two generations younger than I am.  The post-World War II baby boom might have come into play for your family.

And, seeing how much younger you are, I imagine you have a lot of opportunity to ask older family members to get DNA-tested.

Answer 3

Hi Julie! I know that I have more second cousins than first cousins. I have a total of 9 first cousins that I know of. (Unless some have children from previous relationships or the children from another marriage is theirs.) Two have passed away and one I've never met as she was born from an Uncle's previous relationship and doesn't come around. I will have to sit down and think on second cousins.This is an interesting post.

Answer 4

I know of all my paternal 1st cousins, but only 3 from my maternal side. Part of wanting to investigate my past is to find just how many there are and where they went to!

Answer 5

On my German side, I know all of my 14 second cousins. Two of them I only met once, but I met them at least.. On my Serbian side I have 12 (still remember that from the 52 ancestor post last year) and there I met 7 of them. To meet 3 of the 5 missing I would have to go to Croatia.

Comments

Thank you.  I had not thought of the distance involved for people descended from recent immigrants.  I'd think it would be an interesting opportunity to learn more about other cultures.

Answer 6

I am going to admit that I am terrible at this cousin thing. I can't find any second cousins, only first cousins once removed.

I watched a video to understand the difference but I still can't find one. Maybe I haven't added any but is there an easy way to find them?

Please help, now I'm curious!

Comments

That's what I just asked Nelda!

Meanwhile, what I did to find my second cousins was to identify my mother's cousins, and review the children I had recorded for them on my tree.  Would have done the same thing for my father, if he'd had cousins.

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Peggy, after Nelda answered my question, I used my Family Tree Maker software to run a relationship report, which I then sorted by relationship.  It did have the 12 second cousins I already knew I had, but I was also able to count my third and fourth cousins!  I wonder how many people know they can do that? I think I'll post another question to discuss that further.

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Thanks, Julie. I will keep looking.

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Peggy, it sounds like you might be having trouble with the difference between "1st cousin, once removed" and "2nd cousin". The two are confused by people all the time.

It's really not that hard. 2nd cousins are in the same generation. While 1st cousins share a pair of grandparents, 2nd cousins share a pair of great-grandparents.

So while you have two sets of 1st cousins, one set for each parent, you have FOUR sets of 2nd cousins, one for each grandparent. A given grandparent's siblings are your great-aunts and great-uncles on that side, and THEIR grandchildren are your 2nd cousins.

1st cousin, once removed (1C1R) is more complicated, because it means TWO different things. It refers to relatives that are one generation apart, for a start. The first type is simply the children of your 1st cousins. The second type is the 1st cousins of your parents. Note that for the people who are a 1C1R of the first type to YOU, that you are a 1C1R of the second type to THEM.

The uncomplicated thing about it is that it's a mutual relation, that way. You're a 1C1R to all your 1C1Rs! That's in contrast to, for example, your aunt, to whom you are her niece - two different relationship names, depending on the perspective.

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Good explanation, Frank!

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Thanks, Frank.

I think I have it now but now I need to find some!

Answer 7

The funny thing is, the three second cousins that I *don't* know are the only three who live on the same continent as I do. I've met the three from the other side of the globe at least once each. Ditto for the six across the ocean from me, although two of them I would easily pass on the street now -- we were small children when we met.

I know all of my first cousins; I have six total, three on each side. I would not necessarily recognize all of their kids, though -- they've grown up too fast.

The "cousin" I keep in touch with most is actually not a blood relative: she's like a half second cousin, but on the unrelated half. Or I could call her my god-cousin: her parents are my godparents.

Comments

I believe the term you're looking for, for the "unrelated half", is "step".

Answer 8

There are a LOT of only children in my greater family, especially on the Bulgarian side. My family would be very small indeed if all of us second cousins didn't keep in touch!

Answer 9

I have only 17 1st cousins -- all on my mom's side, because my dad was an only child. I know most of them, but a few, I've never met.

As for 2nd cousins, I have lots of holes in my tree, so I guess I've only listed about half of them. I have recorded 85 2nd cousins. I only know a couple of them.

Answer 10

It all depends on how you count.  I have four first cousins (one is adopted) and from those four I have 11 first cousins once removed (1 adopted).  That is a total of 15 first cousins.  I know all my first cousins though most live on the other side of the continent.  

I think I'm closer to some of my second cousins and if you include second cousins once or twice removed, there are a lot of them.  (My grandmother had 12 brothers and sisters.)

Comments

Thanks. I wasn't counting the "removeds."  It doesn't look to me like the others answering above did either.

Answer 11

Since I don't know al my great  grandparents, i Dan't know all my 2nd cousins.  I have personally met some of my half-2nd cousins (on my mother's side) while others i know of  them.  I have 1st cousins who were old enough to be my parents.I have corresponded with some of my double 2nd cousins on my father's side of the family as well.

Answer 12

I have 14 cousins, most of whom I grew up with - one batch is more of an age with my own kids. Two are now deceased. Thanks to my dear sister, who is a great organizer of social events, the rest of us get together now and then.

I know I  have met second cousins as a kid, when the first-cousin parents were still in occasional contact in the summers. Since I don't put living people into WikiTree I had to look them up in an old MacFamilyTree from 2014. I don't know how complete it is, but I have 29 second cousins there (syssling or tremänning in Swedish).

An interesting thing is that I'm a tenth cousin with my children, and the children of my sisters. Also a 9th cousin of my father and an 8th cousin once removed with my mother. Results of pedigree collapse.

Comments

Yes, Eva, that is interesting.  I had not thought about relationships that way.  My parents were fifth cousins, something I never knew until about a year ago.  So that would make me a fifth cousin once removed to each of my parents, wouldn't it?

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At my current stage of understanding, I won't dare to answer that :-)

You've got me working on cousins, though. My problem is that what I have collected is too scattered, since I don't want to put living people in an online tree - and the last four years I have worked almost exclusively with WikiTree. I have bits and pieces of the more recent stuff in MacFamilyTree and some things just in very long text files. So I spent part of yesterday fitting small chunks together in a single MacFamilyTree, starting with the core of first cousins and adding the second-cousins and their families on my maternal grandmother's side + planning ahead for the other second-cousin clusters. I'll keep this tree in tandem with my Wiki-Tree.

So far I can say that I understand what I'm doing ;-)

So yesterday I started...

Edit: I don't know why this was cut off at this point; didn't even notice (I got one of those "are you posting a duplicate?" warnings).

Anyway, I have gone through the second cousins on my mother's side, 23 of them, born between 1940 and 1968, most of them still alive. There will be quite a lot more than 29 when I have gathered the second cousins on my father's side.

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Eva, wouldn't living people be totally private on WikiTree?  Unless perhaps you invited them to join.  Might some of them be interested in genealogy?

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Yes, they would be unlisted, and my watchlist is full enough as it is. IF i can find somebody I can convince to join, I will, of course.

Answer 13

I have 9 second cousins on my maternal side and met 3 of them when I was a child. I assume I have many more than that on my paternal side as my paternal grandfather had 9 siblings. Both my parents only have first cousins on one side of their family so if they had had them on both sides I probably would have a lot more second cousins.

Answer 14

I come from a small family in terms of close relations in modern time.  I only have 5 first cousins and yes I know them all.  

I know more of my farther out cousins like 4th and farther than I do my 2nd and 3rd first cousins.  My farthest cousin that I communicate with a lot is my 13th cousin.  Our common ancestor is in the 1600s.  

It is easier to meet my more distant cousins because they seem to have taken DNA tests while my closer relations have not.

Comments

Laura, I've met many distant cousins through genealogy, sometimes through DNA and sometimes through traditional genealogy.  It's one of the great rewards of the hobby, I think.

Answer 15

Of my documented cousins, I have:

1st cousins: 15

2nd cousins: 107

3rd cousins: 215

4th cousins: 273

5th cousins: 144

I am sure that I have not yet documented all my 3rd, 4th, or 5th cousins, and I am possibly missing some second cousins as well.  I personally know all my 1st cousins except a few, and have met many second cousins but not nearly all of them.

It seems that for each generational degree in my family, the number of members grows by about 7x.  So assuming geometric growth and building from the number of 2nd cousins I have, I should really have about 750 3rd cousins, and 5200 4th cousins.  It looks like I have a lot more work to do if I want to find them all!

Comments

Thank you.  It is true that the farther out you go, the more cousins you are likely to have, but it is also harder to find them!

Answer 16

I have 12 first cousins just from one sibling of my parents.  My Dad had 3 brothers and 5 sisters.  My Mom had 3 brothers and 7 sisters.  So as you can imagine I had a lot of first cousins.  The second cousins are a different matter.  Until I started doing genealogy online just over 20 years ago there were many of them I had never met, our families had spread out all over the country.  I know there are some of them that I still have not met but there are also some that I have been able to communicate with online.  When I get to my other computer with my FTM in it I will try Nelda's way to see if I can figure out how many I have.  Those that I know of and have in my tree that is.

Comments

If I ran the report right I have:

77 first cousins

142 second cousins

150 third cousins

However this does not take into account first cousins, once removed, twice removed, etc.  If I count those I think I have probably 4 or 5 times the amount listed.

I come from a line of very large families and had 3 brothers and 3 sisters myself.

Answer 17

My fathers paternal grandfather had 9 children, 6 of whom grew up to have descendents.

Of all those 2nd cousins. many of them are much older than me and really there was only one family of 4 kids who were the same age as me and my sisters that they were the only second cousins I really got to know.

Most of the other second cousins I know about are just names listed on an old family tree that was compiled back in the 1990s I think.

My fathers maternal grandfather had 11 children, 3 of whom did not have children. I know NONE of any of the second cousins from this side of the family. But my fathers first cousins from that large family are all listed on the family tree that was done in the 1980s. For their children (my second cousins)  I have some names - but not many - and mostly acquired through email contacts  - and very few details about them. I do not know any of them personally at all.

As for my mothers family, well she was adopted and so we are just starting to meet new relatives on that side of the family.

Answer 18

I have 3 first cousins on my Dad's side and 0 second cousins, none of the 3 had children.

I have 10 first cousins on my Mom's side. Of those 10, 4 have no children. I have 8 second cousins who are children of 6 first cousins. I've met them, but no close contact now, different generations.

Comments

Children of your first cousins are your first cousins once removed. Your second cousins are children of your _parents'_ first cousins.

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Yes I know. I have a number of 1c1r in the mix.

Answer 19

I have 7525 blood relatives in my tree. Cousin breakdown is as follows, with first degree or full cousins in parentheses:

6th - 2823  (662)
5th - 655  (36)
4th - 823  (195)
3rd - 517  (103)
2nd - 972  (76)
1st - 398  (9)

Comments

So you mean that, for example, you have nine first cousins, but a total of 398 including first cousins once removed, twice removed, etc.?  

Did you get these numbers from genealogy software as discussed above?  What proportion of your cousins do you think you've discovered?

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Yes to your first question Julie, and I used my genealogy software (Legacy) to extract blood relationships into a comma separated value (csv) file, and subsequently used "Excel" to manipulate the data further.
As for proportion of discovered cousins, other than my nine 1st cousins and possibly 2nd cousins, I will always be adding more cousins. My DNA matches show a lot of individuals in the 3rd-5th cousin range, that I still haven't identified and added to my tree.

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That's a good point, Neil.  When estimating our possible number of cousins, we should take our DNA results into account.

Answer 20

1C: 13 (father's side) + 6 (mother's side) = 19 total. DNA tested are 0+3 = 3. There are a couple on my father's side with special circumstances who I've never met (including one who died when he was less than a week old).

2C: 34+2+25+35 = 96 total. DNA tested are 0+0+5+2 = 7. I've at least met a lot of the ones on my mother's side, but only one on my father's side. I'm not altogether sure if I know them all on my paternal grandfather's side, but the other three sides are completely solid.

3C: 280+?+?+?+?+?+0+? The "280" is not a complete count, but probably at least 80%-90% of it. For the "?" cases, I know tons of people from research, but don't have a count. I'm sure I'll take a stab at some of those sometime, but that'll be a big job.

I have plenty of relatives on my Dad's side, so it's curious that the closest relatives to have tested on his side are 2C1R (there's both kinds). As I go out to more distant relations, that balance shifts dramatically - most of my matches at 3C and especially beyond are on my Dad's side.

Comments

By way of an extreme example the other way, my daughter has 0 siblings, 0 1Cs on her mom's side, 0 2Cs on her maternal grandfather's side, and 0 3Cs on her maternal grandfather's mother's side.

By a little bit of coincidence, on that line she's the oldest (only) daughter of the oldest daughter of the oldest son of the oldest (only) daughter, and it can go on at least a few more generations if you follow the right path. But that's a whole different subject!  

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Very interesting, Frank.  You're getting ahead of me.  I just learned yesterday how to produce an automated list of my cousins, and I have 266 third cousins.  I think that's nearly complete but haven't had time to review my records to try and assess that.

I think that by the time we get to fourth cousins, we are way less likely to be able to produce accurate counts, or even estimates.  Have you estimated your own number of fourth cousins?  (Sorry if you've posted that and I've forgotten.)

Another thing I just began wondering:  When we do estimate our fourth cousins, I imagine three pieces of information:  1. number of identified fourth cousins, 2. our estimates of how complete that number is (i.e. how complete our trees are), and 3. our calculations of expected fourth cousins as you and I discussed in my fourth cousin question.  But there is another piece of information that ought to be relevant--our numbers of DNA matches.  Even given that there is a huge variation, as we've also discussed, in the amount of DNA shared by cousins once you get past the second cousin level, surely we should be able to make some calculation?

Oh--another thing I've been wondering:  I was surprised, when I produced my relationship report, at the number of "removeds" in all the cousin categories.  I probably shouldn't have been surprised!  But I've not even thought about them--the usefulness of the various categories...so many questions!

(Second edit was to delete comments based on my not understanding Frank's post.)

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You're misunderstanding me, about my 3Cs. It's not 280 "plus maybe a few more". It's 280 "plus a bunch of sides of the family that I haven't got a count for".

So you've got me (so far) counting my dad's 2Cs, of which I think I have a pretty solid list (except possibly some more, if I ever find out about his great-uncle, William Johnson).

Guessing that the full count for the 280 is more like 320 and assuming about 2.5 children for each of my father's known 2Cs, my new estimate looks like:

3C: 320+45+85+60+?+?+0+? = 510+?+?+?

The first summation, if I'm not being clear, is adding up the 3Cs due to the 8 great great-grandparents. The result indicates that I still have 3 great-grandparents on my mom's side to estimate.

I'll probably get counting my mom's 2Cs next, but assuming each "?" is about 60 (they're not going to be huge, like the 320), the total will be close to 700, with about half of them on my great-grandfather Standley's side (he had 7 siblings who had at least one great-grandchild). So, again:

3C: about 700

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Yes, I misunderstood what the "80%-90%" applied to.  How are you counting?  Do you have any software that can produce a relationship report for you?  Or are you trying to count third cousins that you don't have on your tree?

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I started using an Excel spreadsheet to keep track of all those Standley-side relatives a long time ago.

OK, now I've counted up my mother's side. Like my father's side (except the 320), it's basically the 2Cs for my mother, times about 2.5. Result:

3C: 320 + 45 + 85 + 60 + 100 + 50 + 0 + 55 = 715

But this exercise has reminded me of a big hole in my maternal grandfather's tree. My grandfather's uncle had 9 children, but the descendants of only one are reflected in that "100" number. The children of the 8 unaccounted for offspring could increase the number of my mom's 2Cs by about 30, and therefore there could be about 75 additional 3Cs for me. So 175 instead of 100, for a total of 790 3Cs.

3C: almost 800?

DNA matches on AncestryDNA:

3C:  23 + 9 + 11 + 5 + 7 + 4 + 0 + 1 = 60 (about 7.5%)