The New York Times reported on September 29, 2007
Dr. Arno Motulsky, a professor emeritus of medicine and genome sciences at the University of Washington, warned, "we give people all the various possibilities and risks and leave it up to them to make a decision. Some might decide a doubling of the risk is not something they want to face. It is not known how many cousins marry or live together" Although the professor was not aginst cousins marrying cousins, his warning sounds too harsh on those who really want to do.
Scientific researches also showed that acute birth defects such as genetic diseseas, mental retardation, etc. have occurred in the cases of cousins marrying cousins.
The Bible speaks as follows:
The nakedness of thy sister, the daughter of thy father, or daughter of thy mother, whether she be born at home, or born abroad, even their nakedness thou shalt not uncover. The nakedness of thy son's daughter, or of thy daughter's daughter, even their nakedness thou shalt not uncover: for theirs is thine own nakedness. (Leviticus 18:9-10 KJV)
Let every soul be subject unto the higher powers. For there is no power but of God: the powers that be are ordained of God. Whosoever therefore resisteth the power, resisteth the ordinance of God: and they that resist shall receive to themselves damnation. (Romans 13:1-2 KJV)
There is no specific verse in the New Testament prohibiting cousins marrying cousins, but there is also no verse reversing the order given in Leviticus 18th Chapter. Some, who want to do against Biblical truths find their own ways to defend their ways, even to the extent gay-marriages and lesbian marriages. I take the warning, "we give people all the various possibilities and risks and leave it up to them to make a decision" very seriously Those, who do not wish to take that warning seriously are at liberty to take their own decisions. This is the end from my part. I have nothing to add to what I have written