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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

To think a 3rd cousin isn't really a relative?

204 replies

CallMeNutribullet · 13/09/2022 15:37

Not really a Royal family thread but inspired by some of the conversations I've seen online since the Queen's death.

I've seen lots of people suggesting the fact that the Queen and Prince Philip were 3rd cousins is creepy and incestuous. To me it's such a distant relationship that I honestly wouldn't even consider myself related to a 3rd cousin. Google tells me you share less than 1% of your DNA with a 3rd cousin and I can't imagine the vast majority of people have any idea who their 3rd cousins are.

Would others see it as a deal breaker in a relationship if you found out a potential partner shared great, great grandparents with them?

OP posts:
FidgetWonkham · 14/09/2022 02:14

Third cousins share great great grandparents. Most people will have lots and lots of them!

ddl1 · 14/09/2022 02:29

YANBU. Most people probably don't even know who their third cousins are, unless they live in small communities, or are particularly interested in family history. Medically, the children of third cousins are no more likely to have birth defects than the children of any parents.

cakeorwine · 14/09/2022 07:32

worriedatthistime · 14/09/2022 01:57

I think most on here don't actually know what a third cousin is and think its their cousins grandchild etc or there mums cousins child

Isn't the 3rd cousin the grandchild of your cousin?

So I know my cousin's.
I also know my cousin's children - these are my second cousins

None of them have had children yet - but f they do, I would hope that we would meet them at out family get togethers - and they would be my 3rd cousin

My Grandma is the grandma of my cousins.
So she would be the great grandma of their children and my child
And she would be the great great grandma of their future children and also DS's children should he father any.

KassandraOfSparta · 14/09/2022 07:35

I also know my cousin's children - these are my second cousins

No, your cousins children are your first cousins, once removed.

WhoppingBigBackside · 14/09/2022 07:41

@cakeorwine , no.

You and your third cousins share great-great-grandparents.

If you consider the Queen's great-grandchildren, say Prince George and Mia Tindall, they are second cousins (Prince William and Zara T. are first cousins).
Prince George's children will be Mia's children's third cousins.

Polyethyl · 14/09/2022 07:42

After reading this I sat down with pencil and paper and tried to work it out. I couldn't even list all my 2nd cousins accurately. (At least 17 of them). I haven't the faintest idea who my 3rd cousins are.

britneyisfree · 14/09/2022 07:47

@WhoppingBigBackside no. According to this thread they are first cousins once removed/ first cousins twice removed etc?

Desert76 · 14/09/2022 07:47

The question is whether my dc know/ have a family relationship with any of my or DH’s mum/dad’s cousins dc. Am I right?

On both sides, they do know one another’s names and have seen photos, but have never met - partly because they, weirdly, all live in Australia or NZ and we live in the UK. They would certainly consider one another to be family.

My Dc do regularly see my own cousin’s dc, who would be their second cousins, at family events - I think it’s quite possible they could still be in touch with one another in 10-15 years time when they might be starting to have children themselves, so the children could well meet, and would presumably be aware they were related.

cakeorwine · 14/09/2022 07:47

So if DS had children, then the children of my cousin's children would be 3rd cousins to each other.

That would be a big family gathering

WhoppingBigBackside · 14/09/2022 07:49

@britneyisfree , according to this thread, but wrong.

A cousin once removed is what Mia Tindall is to Prince William.

WhoppingBigBackside · 14/09/2022 07:55

@britneyisfree
third cousin
[third cousin]
NOUN
a child of one's parent's second cousin.

KassandraOfSparta · 14/09/2022 07:56

britneyisfree · 14/09/2022 07:47

@WhoppingBigBackside no. According to this thread they are first cousins once removed/ first cousins twice removed etc?

It is complicated but taking the Royals as an example....

Zara Phillips and Prince William are cousins.
Zara Philips and Prince George are first cousins, once removed. (one generation removed) - they share grandparents in the Queen and Prince Philip.
Mia Tindall and Prince George are second cousins. - the Queen and Prince Philip are their great grandparents.
Any children which Mia Tindall and Prince George have in the future will be third cousins to each other - their gg grandparents are the Queen and Philip.

WhoppingBigBackside · 14/09/2022 07:57

en.wikipedia.org/wiki/Cousin

NippyWoowoo · 14/09/2022 07:59

Quite simply, third cousins have grandparents who were cousins.

But I did like the poster who explained it as the queen's mother's mother's mother's friend's dog's cousin's great-great-grandchild. Or whatever it was Grin

cakeorwine · 14/09/2022 08:00

Interesting - we do have a lot of family gatherings and our cousins and our children do meet up at them.

But we never had gatherings like that when younger. I know the names of DF's cousins, but we never had family gatherings with them. It was just gatherings with my grandma and her immediate children and their children

A bit of a shame really

KassandraOfSparta · 14/09/2022 08:01

I do think the generalised confusion over cousin relationships and how to describe them is what leads so many to thinking a third cousin is a much closer relationship than it is.

Inertia · 14/09/2022 08:12

ClumpingBambooIsALie · 13/09/2022 16:23

According to this Elizabeth married a guy who was apparently her father's father's father's mother's daughter's daughter's daughter's son, and her father's father's father's father's son's son's son. So (at least) doubly related, but fairly distant on both counts.

Royals are traditionally inbred tho.

By nature he was bendy

diamondpony80 · 14/09/2022 08:12

I know of quite a few 3rd cousin marriages. I know a few 2nd cousin marriages too, but that's a bit more controversial and tends to cause a few raised eyebrows. | don't know any of my 3rd cousins personally, but my parents would know who they are so would have pointed them out if we'd come in contact with them.

ddl1 · 14/09/2022 19:06

I remember a news item that genealogists had found that Obama and Cheney were 8th or 9th cousins!

I have two second cousins who are also each other's second cousin, and they married and had kids who are fine. As, I think, is usually the case. But it may depend to some extent on how genetically diverse the previous generations were. My above-mentioned second cousins have very diverse ancestry, from several different countries and regions of the world. If you have several generations of cousin marriages (e.g. the Habsburgs), the risks increase.

ddl1 · 14/09/2022 19:16

Spinninggyro · 13/09/2022 17:56

Queen Victoria and Prince Albert were first cousins. They both carried the hemophilia gene and their 8th child was affected.

Actually Albert didn't carry the gene. It's a sex-linked gene, so only females csn be asymptomatic carriers. If Albert had the gene, he'd have had haemophilia himself and it's known that he didn't. Victoria must have been a carrier, and one of her sons had the disease, and at least two of her daughters were carriers, and transmitted the disease to their sons and grandsons, with huge effects on Europaean royal families. The current British royal family is not affected by haemophilia, as they are all descended from Victoria's son Edward VII, who did not have the gene,

DappledThings · 14/09/2022 19:22

AprilRae91 · 13/09/2022 16:10

unless they’re not third cousins- my Grandmas brothers daughters children?

Those are second cousins according to the online guide I use.

DappledThings · 14/09/2022 19:32

I also know my cousin's children - these are my second cousins
No, these are your first cousins once removed

None of them have had children yet - but f they do, I would hope that we would meet them at out family get togethers - and they would be my 3rd cousin
These would be your first cousins twice removed.

The first, second, thirdness of the cousiness (I am aware these are not real words) are where it goes sideways on your family tree, where it goes up or down generations but in the same line that's steps of removal.

cakeorwine · 14/09/2022 19:35

DappledThings · 14/09/2022 19:32

I also know my cousin's children - these are my second cousins
No, these are your first cousins once removed

None of them have had children yet - but f they do, I would hope that we would meet them at out family get togethers - and they would be my 3rd cousin
These would be your first cousins twice removed.

The first, second, thirdness of the cousiness (I am aware these are not real words) are where it goes sideways on your family tree, where it goes up or down generations but in the same line that's steps of removal.

That was explained earlier after my reply

DappledThings · 14/09/2022 19:36

My cousins child's children so they're my third cousins but what are they to my children??
They are your first cousins twice removed, not your third cousins. To your children they are first cousins once removed.

LarchDragon · 14/09/2022 19:42

I know who my 1st cousins and 1st cousins once/twice removed are, same with 2nd cousins, but no, not 3rd.

I know that when my 1st cousin has a baby, our children are 2nd cousins to each other. While us as parents will be 1st cousin once removed to the other's child. I suppose my grandchild and my 1st cousin's grandchild would be 3rd cousins to each other.

I guess if you don't know your cousin's well it's not weird.

Yes they share hardly any DNA but I'd still be creeped out by my grandchild dating my cousin's grandchild.