But to be effective witnesses — and productive citizens — we ought to consider why these facts are important. After all, as Saint Peter kindly reminds us, we shouldn’t be throwing the Book until we’re well aware of why we’re throwing it in the first place (cf. 1 Peter 3:15).
There are two reasons we, as American Catholics, should oppose gay marriage: the first has to do with its fundamental opposition to the natural law; and the second with the threat it poses to the stability of family life in our society.
The first reason is the one more closely connected to the Scriptural response. And incidentally, it’s the one tied up with a scientific understanding of human physiology. According to natural law reasoning, each human person — insofar as he or she can think — is able to discern certain moral truths that relate to the way human beings exist. For example, murder is contrary to the natural law, since taking innocent life (i.e., failing to respect the inherent dignity of another) is something we can reason to without special revelation.
The same is true when it comes to same-sex relations. We know that sexual intercourse is a special sort of bond that is aimed at generating children (even if that doesn’t happen all the time). At bottom, the type of action is organic, that is, it unites two dissimilar body parts in a way that can produce an organic (i.e., reproductive) effect. Male-female relationships are the only sort that can embrace sexual complementarity fully; and we honor these relationships — when they’re exclusive and committed — by calling them “marriages.” In short, to reduce marriage to something less than this is to deny our natural understanding of the character of human sexuality. And this is disingenuous.
The second reason we oppose same-sex marriage builds on this. Namely, by denying the name “marriage” to relationships that are not equipped to take on the type of unitive, procreative acts that make authentic marriage a natural good, we resist a growing cultural momentum in favor of destabilizing the family in modern society.
Let’s face it, there’s enough threat to the goodness of family life in things like no-fault divorce, pornography, contraceptive funding and education, etc. — the last thing we need is to relinquish the bastion of family stability, i.e., marriage, to the revisionist foe. Marriages are good for parents, kids, financial security, formation in values, and a whole host of things. And we’d be silly to throw it away.