Marrying a cousin

[pharmaT]

I have first cousins marrying  whose children had issues.  However in addition to their father's being brothers their mothers were first cousins of each other and their paternal grandfather and grandmother were second cousins of each other.

[Josephine]

See this article.

http://www.genetics.edu.au/publications-and-resources/facts-sheets/fact-sheet-18-when-parents-are-relatives-consanguinity

To quote :
"If parents are unrelated, their chance of having a child with a birth defect or disability is between 2% and 3%.
If parents are first cousins, the chance is a little higher at 5% to 6%. This is due to the increased chance that they will both carry the same autosomal recessive mutation, passed down through the family."

My question would be whether a doubling or tripling of the chances can be accurately described as being "a little higher."

Yes, overall, 6% is a lot less than 94%, but 6% is three times the rate of 2%.

And then, are we dealing with 6% of 100 people or 100,000 people? If the latter, the number of potentially affected children would rise dramatically.

(I know you're not the originator of the quote; my comment is not directed at you but more in general.)

[cristeen]

I also have a few instances of first cousin marriages & at first thought this was unlawful, Google to the rescue!
I do get the impression from two of my examples that the practice was not approved by the local community/families. One couple chose to marry in the nearby town rather than the local church where siblings had married and almost immediately moved to Scotland. Another I was told had caused upset in the family on her marriage and also had moved away from the home village. This may have had more to do with her widowed father & four brothers losing their free housekeeper though!

[TropiConsul]

You might want to take a look at the history and the genealogy of isolated settlements in North America.  You will find that marriage to a first cousin was inevitable in remote communities unless the child of the first generation of settlers abandoned family investment and took  to the road in order to explore opportunity in another community at further remove. 

[JanPennington]

As mentioned before one marriage between cousins will only increase health problems a little but if cousins marriages continues through several generations there will be greater problems.
The link below includes a family tee for King Charles II of Spain and shows what happens when royalty are restricted in who they can marry

http://www.genealogyintime.com/NewsStories/2009/April/inbreeding-of-spanish-royalty-page1.html