When did marrying a cousin become socially unacceptable?

[LionBird]

I'm a big Agatha Christie fan and noticed there are quite a few references to cousins being in a relationship. I'm rereading Taken at the Flood currently, which is set in 1946, and the main character is engaged to her cousin and nobody seems to think it's strange! Obviously it was quite common in royal circles too in the 19th century but post-WW2 isn't that long ago so I'm not sure how and when it became unacceptable to have a relationship with a cousin - can anyone shed some light on this?

My great-grandparents were first cousins. My grandmother (in her 90s) is defensive about it and always says how they asked the bishop beforehand. They had eight kids - one died in infancy. But no real abnormal health issues with the rest. That said, one had three kidneys.

I think there's possibly still slightly more risk of certain conditions, but clearly less so than first cousins.

People have a little knowledge and have decided they are geneticists.

In children of unrelated couples, the risk of congenitall_ and genetic including recessive problems is usually estimated at about 2-3 per cent. First cousins have a slightly higher risk of recessive problems. At about 4-6 per cent, this risk means a 94-96 per cent chance that their child will be perfectly healthy. A cousin couple is thus more likely to have a healthy child than to have a child with a recessive problem.

A one off first cousin pairing probably won't cause any birth defects
But in communities where generations of first cousin,s marry and have children any genetic disorder ,s are going to continue to be passed on.

The risk of a birth defect in a baby born to first cousins is around 5-6%. Which is roughly double the risk to an unrelated couple. It's the same increase in risk as babies born to mothers aged over 35.

ETA cross post with several others!

No real issues.....but 'one had 3 kidneys'.....also we don't know why the little one died.....

It is incest

Are you trying to justify 1st cousin marriage?

It's not actually, though it feels like it to many of us.

It can lead to health issues if you have a recessive genetic condition, but that's only more likely not guaranteed.

I know two people who married their cousins. Both didn't know their cousin until they met in adulthood, as in they may have met once or twice when small, but not beyond that. One was a bit Romeo and Juliet, as in the two sides of the family were estranged.

Both have had 3 children with no known health issues except one child has very poor eyesight, but as dad has too, I don't think that's a recessive gene.

I think I've got 20+ cousins, some I've never met and the last time I saw any of them was at a funeral about 12 years ago when I met 3 of them. I have no idea how many 2nd cousins my kids have, could easily be 40 or more. I think I met one of them about 30 years ago, just once when they were visiting the UK, they live the other side of the world.

A one off cousin pairing can and does cause defects. It's wrong to say it probably won't.

Legally it's not but it' feels gross to me.

@Nolegusta True. But it wasn't out of the ordinary then for infant mortality in ooor families. On the other side, 4 survived out of 13 babies and there was no cousin marriage involved.
I'm not recommending it! I reckon they probably all got off quite lightly. I'm always surprised that it's not illegal tbh.

Wouldn't you realise at some point that you had the same great grandparents. Most people talk about their family?

In Iceland they have an app that people use to check if they're related before they date.

So true.

It’s the repetition of cousin marriages in
a family that chucks out horrible birth defects - look at Russian royalty.

Other people do it to keep land and money in the family.

Incest isn’t that frequent in other animals.

As with a lot of nature, break the rules once and you’re fine - carry on and you regret it.

This is a bit of an in joke in our family.

My paternal grandmother had 52 grandchildren when she died, and most of us still live in the same town she was brought up in. My nephew, has on occasion, text his mum on a night out and asked ‘ am I related to xxxx’

I do know all of my cousins and the next generation, so that would me second and third cousins, know, or know of each other also as we have met at family occasions and events,

It isn't a new thing, read up about Tutankhamen for example.

I didn't say it never causes problems ,I said it probably won't do you understand what probably means?
I'm not advocating cousin marriage I think it's pretty grim but it is legal.

I mean there is also an element of randomness in genetics and luck was possibly on their side. **

I am mid sixties and can remember my own grandmother saying this was unacceptable. I think it's always been that way in British culture?

@Nolegusta I think so too.

I wonder if they meant cousin in a very loose sense, so not a first cousin, more like very vaguely distantly related - 3rd cousin twice removed or similar.

It’s quite common in the Irish travelling community and as far as I know requires a dispensation.