But of course, the quote from Cardinal George makes no religious argument at all. He merely states the biological facts: humans come in two complementary sexes. Opposite sex pairs are needed to engage in specifically marital relations. Thus, same sex marriage is simply an impossibility.
Now, if the14th Amendment is to be read as endowing a right of homosexual marriage, one would expect to find some evidence in the text itself, or in the legislative intent, or in the argumentation leading up to its adoption, that it was intended to bestow rights of marriage to same sex couples. But one finds no such thing. Indeed, if one were to have asked the question as to whether the amendment promulgated a right to same sex marriage, the answer would have been negative. Had the right of same sex marriage been there, one might have expected some reaction from those present at the time, whether favorably or unfavorably. But no one mentions it. No one suggests it.
So if one wishes to find same sex marriage in the Constitution, it will have to be put their by Constitutional amendment.