Should it be illegal for 1st cousins to marry?

[brasty]

My DP's parents are 1st cousins, and DP has a genetic illness. Marrying your 1st cousin increases the chances of genetic illness. So I wonder if we should simply make it illegal for 1st cousins to marry? Obviously anyone married would stay so, it would only apply to new marriages.
AIBU?

Similar to Andiesays my grandparents were first cousins and I have thought nothing about it.. they had 5 children and all went on to have between 1-3 children each, all of my cousins have also gone on to have between 2-4 children each ( 9 grand children) and we are now up to 16 great grand children. All I can say is not one of us have any birth defects physically or mentally and no disabilities at all and we are a large family! All extreamly healthy. So I don't think any ones doomed if they are from first cousin relations. But I can understand that repeated acts could start to cause issues .

Very wrong - think about the genetic mutations down the line.

I once posted about a v close family member whose started dating their 1st cousin and WIBU to think it was gross and not pretend that I'm happy for them. I was told I'm disCUSting and that if it were their family member they'd be thrilled. Yeah right

genetic mutations
Are you sure about that?

The problem isn't that it increases mutations. It's that it exposes the ones that are there.

The problem is this: we each have two copies of most genes. There are lots of variations on each gene, tiny variations usually but sometimes quite big errors.

Some of these errors are dominant - you only need one copy to cause a problem. Example: Huntington syndrome.

Most however are recessive so you need two copies to cause a problem. Example: cystic fibrosis.

The problem with cousin marriages is that you're much more likely to uncover these recessive genes this way. The more related you are, the more similar your genes are and the more likely you'll inherit an error from both parents in one gene.

We ALL carry potentially dangerous mutations. They happen at a frequency of roughly 10,000 'letters' per cell per day. We are astoundingly good at repairing them. But we all carry potentially dangerous mutations.

It's not an absolute - it doesn't guarantee illness, but it does strongly increase the likelihood. And when you get multiple incidences in a community or family then it's associated with a significant degree of mortality and morbidity.