It has been common knowledge for millenia that the offspring of two close relatives are more likely to suffer from birth defects and inherited disease than those conceived from parents more distantly related.
Even though understanding of why this might be did not come until the foundations of the science of genetics by Gregor Mendel in the late 19th century for centuries there have been laws and customs in place to prevent the parings of people who are closely related. In fact I believe the incest taboo is inbuilt in most of us.
My own church bans first cousin marriages I believe (I really should check but I haven't the time right now).
However first cousin marriages are common amongst Pakistani Muslims in Great Britain apparently. And these are often arranged marriages.
And it would seem that the evidence is there that amongst this group there is a far higher incidence of birth defects and inherited disease than in the general population.
Phil Woolas a Cabinet minister in the British parliament and who represents an electorate with a high population of muslims has raised this issue, igniting the inevitable charges of Islamophobia and racism.
What this illustrates to me is the way political activists, politicians and the like attempt to suppress unpalatable facts or those which stand in the way of their personal agendas by use of what are really hate words.
There are laws, some civil, some religious on who can marry whom and they have evolved for a reason, reasons maybe not fully understood even to this day but at their heart is an understanding of the necessity for humanity to produce a healthy new generation to carry on from where we leave off.
And slowly but surely the social architects are undermining these laws which is probably the greatest threat to the future of humanity we face today.