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[CLKD]

An MP is suggesting that it becomes illegal for 1st cousins to marry due to the possibility of children from the union having health problems.  I can't find which health issues he is suggesting.  It was common for cousins to marry in many cultures in fact my paternal Grandparents were 1st cousins. 

Is there any hard evidence that children are more likely to suffer health issues than those from other relationships? 

With all these sperm banks set up in recent times, the likelihood of people having children without being aware of a relationship link is increasing.  Some R now finding over 20 sibling links through DNH testing.

Certainly in some US States people intending to marry have to undergo health discussions B4 a licence is granted. 

[Sophya]

Yeah, there’s a slightly higher risk with first-cousin marriages—like, birth defects go from around 2-3% in the general population to about 4-6%. It’s not a huge jump, but it’s there because cousins share more DNA. If the family doesn’t have a history of genetic conditions, the risks stay pretty low.

That said, cousin marriages have been super common in a lot of cultures for ages. It wasn’t weird—it was practical.

[Nik2502]

It’s more a problem when generations of first cousins marry first cousins

[CLKD]

Any idea which birth defects and how often these might occur?

[Nik2502]

autosomal recessive disorders such as
oculocutaneous albinism
alkaptonuria
Bartter's syndrome
cystic fibrosis
endemic goitrous cretinism
familial amaurotic idiocy
galactosaemia
Gaucher's disease
glycogen storage disease
phenylketonuria
Wilson's disease
xeroderma pigmentosa
25% increased risk
Plus 6% increased risk of other genetic abnormalities (max 3% risk in non related marriages)

[Kathleen]

Hello ladies

The list of problems that can result from inter marriage is formidable but I believe their likelihood increases when first cousins marry over several generations.

I also think that the occasional first cousin marriage was likely more common in the past, given the number of isolated communities and lack of travel.

Having said that my daughter traced our family tree and found a relative who left his village at age fourteen and went to London where he was looked after by his aunt and he ended up marrying his cousin. They had three sons and there was no hint of disease or deformity.

Take care ladies.

K.

[HellsBells]

The risk of first cousin marriage birth defects is an increase of 50%. That is compounded by generations doing the same thing over and over again down the generations. The NHS employs specialist staff to deal with 'close relative marriages' and there is a burden on the NHS as a result. It is a choice with little thought for the children of the marriage and much more about the familial ties. To deliberately risk a child suffering for their whole life is reckless at best and cruel at worst. Some of the conditions suffered by the children are horrendous. It is a practical approach (banning it) for which there is a great deal of supporting evidence. Why do we get vaccinated or wash our hands? To reduce the risk of disease - a practical choice. It is also a burden on a free health system with limited ££ resources.

[CLKD]

Interesting- which particular birth defects are common from the list ?  Is this World wide?

[CLKD]

Cystic Fibrosis Foundation:

Cystic fibrosis is a genetic disease. People with CF have inherited two copies of the defective CF gene — one copy from each parent. Both parents must have at least one copy of the defective gene.

People with only one copy of the defective CF gene are called carriers, but they do not have the disease. Each time two CF carriers have a child, the chances are:

25 percent (1 in 4) the child will have CF
50 percent (1 in 2) the child will be a carrier but will not have CF
25 percent (1 in 4) the child will not be a carrier and will not have CF
The defective CF gene contains a slight abnormality called a mutation. There are more than 1,700 known mutations of the disease. Most genetic tests only screen for the most common CF mutations. Therefore, the test results may indicate a person who is a carrier of the CF gene is not a carrier.

[CLKD]

Bartter's syndrome - first diagnosed in 1960.  No suggestion that this is due to first cousins marrying. 

[SundayGirl]

endemic goitrous cretinism

Now called Congenital Iodine Deficiency Syndrome or CIDS. And has nothing do do with cousins marrying cousins. Or genetics for that matter. It's due to the mother not consuming enough iodine during pregnancy.
 
Very rare nowadays as all newborns have thyroid function tested via the heel pr1ck and if discovered, easily 'cured' with thyroid hormone replacement.

[SundayGirl]

 

With all these sperm banks set up in recent times, the likelihood of people having children without being aware of a relationship link is increasing.  Some R now finding over 20 sibling links through DNH testing.

I suppose in an ideal world, all sperm and egg donors should have genetic testing before being allowed to donate. The same with all recipients.The results should be recorded against their particular sample/egg and that sample/egg should not be offered to a recipient if they also test positive for that particular genetic mutation.
It would reduce the risk of any hereditary issues.

It wouldn't stop men from 'fathering' multiple children though.

[CLKD]

I think that the cat is out of the bag on that one! 

[HellsBells]

https://hansard.parliament.uk/commons/2024-12-10/debates/6A325A71-434B-42FF-AC9F-FF8C6FD85B00/Marriage(ProhibitedDegreesOfRelationship)Bill#:~:text=Health%20consequences%20can%20include%3A%20recessive,including%20facial%20clefts%20and%20cardiovascular

[SundayGirl]

Thanks HellsBells that was a very interesting read 🙂

Whether the bill becomes law or not, I doubt that it will prevent all closely related couples from marrying. Apart from the fact that if it's part of some cultures and the couple can travel to another country where it's legal, there's also the children of donors who have no idea of and don't wish to discover anything about their genetic parents.

It will never be stamped out fully no matter which side of the fence you're on.