Loving v Virginia (1967) - Interracial Marriage
It should also be pointed out that in the case of Loving v Virginia (1967), SCOTUS
upheld marriage as a Constitutional right that was to be free from governmental
interference. Now, before there are howls, yes, the issue in Loving was race. However,
genetics is not the test for whether a group is a suspect class.
(http://en.wikipedia.org/wiki/Suspect_class)