For the most part, I think that's a worthy goal. While I think marriage equality has tremendous symbolic importance and should be pursued for that reason alone, in general I think the manner in which law nurtures relationships should be primarily designed to a) provide basic protection to all members of the relational unit (especially particularly vulnerable ones, such as children) and b) give people the tools to support and protect the people important to them, regardless of status. When I get married, I definitely want my wife and children to receive the full panoply of rights and benefits I receive. But if, God forbid, my parents need to turn to me for support in their old age, I'd like that same assurance that I could provide whatever resources I could to them as well. As such, I think the role of law is not to mandate certain types of relationships (beyond the aforementioned stipulations about protecting the vulnerable), but to provide an "enabling environment" for relationships that already exist. For gay couples then, the wrong question to ask, I think, is whether or not the state should be encouraging or discouraging their formation (and/or them raising children). Gay couples already exist, and they already are raising kids. The question for the state is how we ought treat these relationships, what obligations we have to its members, and how we can create the best possible environment for flourishing and human freedom within such a context of choice.
I do wonder if the group has run ahead of itself when it makes statements like this:
For example, who among us seriously will argue that the following kinds of households are less socially, economically, and spiritually worthy?
Committed, loving households in which there is more than one conjugal partner.
If that is (as it sounds to me) a reference to polyamorous relationships, then they've probably gotten a bit ahead of the rest of the population. But by-and-large, I think this is an interesting document, and one well-worth considering.
The H/T goes to Rob Vischer, who asks (fairly, in my view) for greater elucidation of the theoretical underpinnings that are behind the statement.
One or more of the following premises seems to be operative: 1) individuals' structuring of their household relationships is unaffected by the law's content; 2) all categories of household relationships are of equal value to the long-term health of communities; or 3) regardless of the comparative social value of relationships, the government overreaches if it tries to reflect that comparative value in public policy. Whichever premise is doing the work here, the statement would benefit considerably from bringing it to the surface where it can be unpacked and engaged.
I'm not sure this is (or is intended to be) an exhaustive list, but I would probably come down on a modified version of number 3. I've seen some evidence that two-parent homes are better than one-parent homes for raising children, no evidence that heterosexual homes are better than homosexual homes for the same. But regardless of what the evidence is on either of those counts (or any other family structure, not to mention the numerous cases where there are no children to speak of), I think that whatever marginal benefit might be accrued from forcing people into the "ideal" relationship is wildly outweighed by the harms that come from not giving benefits to already existent non-ideal relationships. That is, even if one could find an ideal relationship "type", I believe the benefits of encouraging that type to the exclusion of all or most others are negligible compared to the harm suffered by those persons who are not and will not become part of said relationship type. For example, even if it could be shown that heterosexual families are better for children than homosexual ones, depriving benefits to homosexual families would do far more damage to the children of such unions than could be justified by whatever benefits might come out such a deprivation.