http://www.nytimes.com/2002/04/04/science/04COUS.html
The above link is to an article entitled "Few Risks Seen to the Children of 1st Cousins." In it, it describes how this guy Dr. Arno Motulsky from the U of Washington feels that 1st cousin incest is fine, and should not bear the weight of social taboo. Some good quotes:
"Contrary to widely held beliefs and long standing taboos in America, first cousins can have childred together without a great risk of birth defects or genetic disease, scientists are reporting today. They say there is no biological reason to discourage cousins from marrying."
"Twenty-four states have laws forbidding first cousins from marrying, and seven states have limits like requiring genetic counseling. But no countries in Europe have such prohibitions, and in parts of the Middle East, Africa and Asia, marriages between cousins are cnsidered preferable."
And then finally...
"The report made a point of saying that the term 'incest' should not be applied to cousins but only to sexual relations between siblings or between parents and children."
Wow. This is SOOO becoming a part of my incest play class.