There is a new academic paper defending the idea that marriage of the "Leave it to Beaver" variety is a metaphysical fact (and no, I'm not kidding):
Marriage is the union of a man and a woman who make a permanent and exclusive commitment to each other of the type that is naturally (inherently) fulfilled by bearing and rearing children together. The spouses seal (consummate) and renew their union by conjugal acts—acts that constitute the behavioral part of the process of reproduction, thus uniting them as a reproductive unit. Marriage is valuable in itself, but its inherent orientation to the bearing and rearing of children contributes to its distinctive structure, including norms of monogamy and fidelity. This link to the welfare of children also helps explain why marriage is important to the common good and why the state should recognize and regulate it.
The paper is at the link. Here is one critique of the academic variety; here another, slightly less academic, but equally poignant. I'm not going to bother with the arguments, at this point, because I think that matter has been resolved–however much the Harvard Journal of Law and Public Policy might disagree. Well, ok, just one.
Our organs—our heart and stomach, for example—are parts of one body because they are coordinated, along with other parts, for a common biological purpose of the whole: our biological life. It follows that for two individuals to unite organically, and thus bodily, their bodies must be coordinated for some biological purpose of the whole.
That sort of union is impossible in relation to functions such as digestion and circulation, for which the human individual is by nature sufficient. But individual adults are naturally incomplete with respect to one biological function: sexual reproduction.
I suspect questions are massively begged on the idea of "biological purposes"–and I think "organic" uniting is probably different from anything you can get at your Whole Foods. Whatever their meaning may be, the hilarious part/whole purposes analogy cries out for inclusion in one's Introduction to Logic text. My liver has a function, ergo, ipso facto you must marry me.
Let's go ahead and suppose that lots of arguments can be dreamt up for Leave it to Beaver marriage. They're all going to suck, because they presume stuff that just can't be presumed, or they try to establish things as facts that can't be established as facts without the presumptions.
I wouldn't even consider this an academic argument at this point–one whose outcome matters not. The outcome of this argument matters a lot. It's just that we've already seen it. Does this mean, real question here, that we have duty not to entertain this kind of argumentative detritis?