Here's Jon Rauch on why gay marriage should be normalized:
Suffice it to say that, in a society riddled with divorce and fatherlessness, family policy’s essential task is to shore up marriage’s status as a norm. In a world where gay couples look married, act married, talk married, raise kids together, and are increasingly accepted as married, the best way to preserve marriage’s normative status is to bring gay couples inside the tent. Failing to do so, over time, will tar marriage as discriminatory, legitimize co-habitation and other kinds of non-marriage, and turn every successful gay couple into a cultural advertisement for the expendability of matrimony.
, naturally. It's interesting to see how to get to gay marriage from a traditionalist path.