Maggie: Thanks for guest-blogging with us this week. You raise some great questions. Historically, you are correct when you state:
Sex makes babies, Society needs babies, babies need mothers and fathers.
My question (and I am genuinely asking--I think that this is an unusually difficult issue to which I certainly don't have any easy answer): if marriage arises from procreation, what impact does modern reproductive technology have on the definition of marriage? With invitro fertilization, sex is no longer a necessary condition for producing a baby. Two women could have a baby with donated sperm; two men could have a baby using a surrogate. At that point you have procreation and two parents, just not male and female.
My current thinking, for what its worth, is that the best argument in favor of traditional marriage may be a Hayekian (and perhpas Oakeshottian) one--marriage by long and western tradition has been one man and one woman, and that the long-lived and widespread nature of the tradition gives rise to a presumption that should be rebutted only by relatively strong evidence.
[If you are interested in my thinking on the issue of same-sex marriage, my thoughts are continued under the hidden text]
Having said that, it could be argued that this puts heavy weight on the scale in favor of preserving tradition and providing a compelling reason for overturning it by constructive rationalism. Such reasons certainly can be provided, but I believe that they must be provided in terms of compelling moral and/or consequential reasoning (such as was the case with the abolition of slavery for instance). Not to mention, of course, the clear and massive negative externalities imposed upon nonconsenting parties from such institutions as slavery and discrimination. Here, by contrast, the externalities imposed by denying the benefits of particular types of marriages are not nearly as clear or large as cost-externlizing traditions.
Identifying when the burden has been carried to rebut a long-lived and widespread tradition can be a difficult question in any given case in any given historical context, and there will certainly be room for disagreement. To my mind, in light of what is known today, the case for recognition of same-sex marriage has not sufficiently rebutted the presumption of preserving the traditional definition.
On the other hand, I could see the evidence accumulating in such a manner that at some point in the future the argument could be carried--for instance, if the rush of alternative reproductive technologies leads to a growth in the number of children being raised by same-sex couples and available empirical evidence demonstrates that recognizing such marriages would indeed further the traditional purposes of marriage and would not undermine the strength of traditional marriages. It could be that if people are having children, it is better to have them raised by two people involved in a long-term relationship than one person or a more temporary relationship, in that this allows for the possibility of specialization and division of labor within the family (on the other hand, the entry of women into the workforce has also reduced the strength of this argument about the traditional division of labor and specialization within the family).
Perhaps my thinking can be clarified by comparing it to my current thinking about how both traditional and same-sex marriage can be distinguished from polygamy. While I see same-sex marriage as a relatively close call and somewhat fluid at the current time, I think at the current time the argument for recognizing polygamous marriage is weaker and even more speculative. It is not clear that the marginal benefit of household specialization is much larger from adding more parents to a given household, and I think that there are clear benefits of societal stability and productivity of marrying men into monogamous relationships. Polygamy for some men, of course, means that other men will not be married and procreate at all. I suspect that the overall impact in terms of the damage that can be done to a society by a posse of unmarried men, and the oppressive and unproductive social investments that have to be made to control them, suggests that the net costs of permitting polygamy clearly outweigh the net benefits. As I noted, the costs and benefits of same-sex marriage are closer. This assumes, of course, that the number of men and women engaged in same-sex marriages remain relatively small and basically symmetrical (i.e., that the marriages do not displace a sufficiently large number of men who want to marry women so as to give rise to some of the social concerns triggered by polygamy).
This also implies that the argument for or against recognition of certain sorts of marriage must turn on something more than the private preferences of those involved, but some social benefits that arise from the institution. On this point I think that Maggie is clearly asking the right questions. After all, marriage is defined as a legal concept by the state, and so I think there is inherently a social, and not merely private, element to the analysis.
Now Maggie's response may simply be that we should place greater limits on the use of alternative reproductive technologies or encourage a return to greater household specialization. But I would be interested in hearing how she wrestles with the issues raised by modern technologies that uncouple procreation from male-female sex and the implied male-female child rearing that results.