My degrees are in chemical and biological sciences, so I understand the genetic aspect. I was merely curious as to what you guys thought. And if everybody thought so for the same reason-genetics, which is what most people cite as the primary reason. The thing is that 6.25% chance is incredibly small. Overweight and especially obese women have a much higher rate of producing children with birth defects-they may not have dominant genes for it, but the result is about the same. Yes, for repeated marriages among cousins, the chance becomes higher and sometimes you can even see these defects. But many of the laws were made in the late 1800s and early 1900s, before things likes DNA and chromosomes were known.
"While some consanguineous couples are at high risk of conceiving a child with a genetic disorder, they are a small minority. Thus a multi-population meta-analysis has indicated an excess infant death rate of 1.1% in the progeny of first cousins, and even this figure may be compromised by inadequate control for non-genetic variables." This is from a reputable journal-Early Human Development (2010)
But I was just wondering why the impetus behind it was so strong that the marriages had to be outlawed when so many other risky things for babies are not.
Regardless, this is not the point behind the original post. Sorry it got sidetracked.