Originally Posted by cosmos
the genetic defects and mutations associated with inbreeding are well known and substantial. its not illegal because of a moral issue, its illegal because its ending lives and forcing deformed children to grow up in torturous enviornments
But the function of marriage is not to reproduce, but to celebrate your love for someone. If we're using reproduction as an issue, why not ban gay marriage, because they can't reproduce at all?
Besides, the chances of a child getting serious defects from incest parents are only slightly higher than those of one from non-incest parents.