[Lunatic Fringe]

Hmm, in the post you responded to... I said:

"one can argue against them (incestusous relationships), that genetic defects as a result of that type of relationship would threaten the quality of life in American society."

[Wordsmith]

Yes, you did. If the only reason for banning incestuous marriages is because of the possibility of genetical impaired offspring, then what reason is there to ban marriages between brothers, or between a mother and her daughter?