to think it's obvious that cousin marriages increase the chances of birth defects

(271 Posts)
kim147 Thu 04-Jul-13 22:35:34

www.bbc.co.uk/news/uk-england-leeds-23183102

A study has shown that there is an increase in birth defects when first cousins get married.

No surprise - it's genetically pretty obvious. Yet apparently this subject has not been taken seriously and apparently it's ok because it's allowed in Islam.

The chance doubles from 3% to 6%

37% of babies of Pakistani origin had parents who were first cousins.

I'm just surprised they needed this study. Everything I know about genetics would indicate that the chances of getting 2 defective genes increase in families and that includes cousins.

Cheeseatmidnight Thu 04-Jul-13 22:38:39

I know cousins who married and had children, all fine, but they ALL look the same.... They look alike and the children look like them...spooky

justabigdisco Thu 04-Jul-13 22:39:25

I find the BBC health website often carries stories based on research from the University of the Bleedin' Obvious.

kim147 Thu 04-Jul-13 22:43:12

I know it's not the same but when I was studying genetic diseases, the Ashkenazi Jews were used as examples where birth defects were high because the community is so close that it's likely you'll get two recessive genes. There's limited opportunity to develop variation.

Apparently it's illegal to marry cousins in the USA. I think.

Soupqueen Thu 04-Jul-13 22:43:51

"it's ok because it's allowed in Islam"

Eh?
It's perfectly legal in the UK, Muslim or not.

kim147 Thu 04-Jul-13 22:45:41

That was what an interviewee said - he thought there was no risk because otherwise God would not have allowed it.

AFAIK it's legal to marry your cousin in the uk whatever your religion. It's just not particularly prevalent.

RunRabbit Thu 04-Jul-13 22:46:32

What's your point? hmm

Latara Thu 04-Jul-13 22:46:53

One of my cousins asked me out (Jeremy Kyle moment there!)... I said no but he's still keen! grin

Must refresh before posting...

Eyesunderarock Thu 04-Jul-13 22:48:46

It depends how often the marriages happen within a select community, so cousins marrying cousins and their children doing the same, and their children.
There was a study done on this several years ago, and I remember one from decades ago looking at instances of polydactylism and dwarfism within....the Amish I think.

LRDLearningDomHome Thu 04-Jul-13 22:50:48

I don't think it's that obvious, no.

The report I read of that study pointed out that they had to be very careful to exclude other issues such as economic deprivation - like it or not, the populations in the world where people still routinely marry their cousins are not typically the wealthiest, are they? This study was trying to check that it wasn't to do with that, which is a good thing, I think.

I certainly can understand people not realizing if they'd been brought up to feel it was expected. Increasing a risk to 6% is still small enough, you wouldn't easily notice it the way you might if it were something dramatic like 50%, and people naturally look at their own experiences and generalize from them.

I've got to admit, I didn't get brought up with the squeamishness many people seem to have about marrying cousins - it's legal, and I'm not remotely close to my cousins so I don't have that 'ewww, family' reaction (though I do have plenty of 'ewww' generally with them). I suspect that affects how I see it.

kim147 Thu 04-Jul-13 22:52:46

My point runrabbit is that it's blindingly obvious that such marriages will increase defects. I'm just surprised that the initial reasons were put down to poverty and deprivation when the most common cause of birth defects are the genes.

It's taken this large study to prove this.

DuttyWine Thu 04-Jul-13 22:52:51

I did a course on this subject as part of my work... I understood it as this, the risk increases from 1 in a 100 to 1 in 4 if someone marries a cousin with the same genetic disorder.
The lady running the course said they were trying to encourage genetic counselling before cousin marriages were arranged.
It was really interesting, one lady on the course had married her cousin and she said she wished she had been offered genetic counselling before the wedding.

Latara Thu 04-Jul-13 22:53:10

Yes, like LRD I wasn't close to my cousins growing up; in fact I only met the cousin who asked me out for the first time a year ago.

LadyIsabellaWrotham Thu 04-Jul-13 22:54:41

Agree with Eyes that cousin marriage as a one-off is a relatively small increased risk, but when it becomes the norm as in the nineteenth century European royals or some South Asian rural communities then it leads to genetic collapse and the risk increases seriously.

Eilidhbelle Thu 04-Jul-13 22:55:09

I don't get the 'allowed in Islam' bit - it's allowed in loads of religions and countries. Including Britain.

kim147 Thu 04-Jul-13 22:55:49

I'm coming at it from a very scientific background. When I worked in medical genetics, we had this thick book (2 volumes) of genetic diseases. Absolutely loads of them but very rare.

But the chances of getting 2 rare defective genes dramatically increase when you procreate with close family.

I'm just surprised this data and investigation has only just been done.

puddeycat Thu 04-Jul-13 22:55:49

My paternal nan and grandad were 1st cousins and their dads identical twins! Perfectly legal to marry 1st cousins back in the 1940s! My dad aunt and uncle are all fine and so are us kids. grin

LRDLearningDomHome Thu 04-Jul-13 22:55:57

Is it 'blindingly' obvious? confused

I forget how much we did about genetics at school. Tiny bits, IIRC - mostly stopping with what I've more recently heard is inaccurate stuff about dominant/recessive eye colours.

I don't think you can expect everyone to have studied it in detail.

I do get that it is worrying, but I feel a bit uncomfortable with the idea of saying it's 'blindingly obvious' and it was only Islam that made people do it.

I'm just glad they have done such a careful study and it's being so well publicized.

carabos Thu 04-Jul-13 22:56:33

If you read around the subject, you will discover that the absolute numbers of affected children are very small, but there are often multiple instances of miscarriage, stillbirth and disability within a single family.

The recommendation is that cousins who know there are genetic disabilities in their extended family should take advice and counselling so they can better understand their own risks. No-one is suggesting that action should be taken to prevent or limit cousin marriage.

Latara Thu 04-Jul-13 22:56:58

Wasn't Queen Victoria the cousin of Prince Albert??

littleginger Thu 04-Jul-13 22:57:01

I find it odd to have more than one link between you and your child, ie, parent / child and second cousin / cousin once removed. Creepy!

LadyIsabellaWrotham Thu 04-Jul-13 22:57:20

...sorry that's pedigree collapse, not genetic collapse.

Essexgirlupnorth Thu 04-Jul-13 22:57:24

It even more of a problem when your parents are also cousins and your grandparents.
It is obvious but think cultural sensitivity stops people talking about it.

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