German incest couple lose European Court case

[CCIP]

Originally Posted by Krauter

I completely agree that incestuous relations, to be precise, sexual relations are not normal and naturally speaking are not in the least bit close to natural. .

How do you know this? There is a lot of incestuous behaviour observed in nature and among primates particularly (just do a quick google search - there is a vast amount of academic material on this subject out there). What makes it unnatural, then, and how can we prove this? I'm afraid a lot of it is simply a common-sense assumption that the loss of genetic variety makes it unnatural, but in fact that in itself is pretty poor reasoning to justify the 'unnaturalness' of it alone.