"It seems a wildly anachronistic query and, if situated in the historical context of ancient China, might be immediately rejected. But a modern Confucian perspective, one that seeks to distill the core elements of The Analects and apply them universally, could be affirmative."So what is are the core elements of Confucianism? I haven't read him in about three or four years, but as I remember it, he focuses on how the young man is to fulfill his obligations to close relations, moving outwards from the primary filial relationships. It's sort of how not to be a dick. There was an old saying among Chinese bureaucrats that the ideal life meant being "a Confucian by day and a Taoist by night", and Confucius is still a good guide to social relations.
"If you woke me up in the middle of the night and asked: what is the key to Confucius? I would say: the daily care and cultivation of loving family relationships. He emphasizes the respect we owe our parents, but he also tells us to "cherish your children" (2.20). Indeed, we should care for our parents precisely because they cared for us when we were young. The flow of family duty runs forward and backward in time simultaneously: we are bound to both our children and our parents."What about gay adoptive parents? He points out that Confucius disdains sex, but suggests this doesn't necessarily clash with our contemporary understanding of gay romantic relationships any more than it does with how we understand straight relationships. To me, though, the most important thing is that Confucius, as opposed to many thinkers in the West, doesn't see marriage as primarily a religious institution. The Abrahamic faiths tend to see marriage as part of God's plan for promoting the creation of life. Secular societies see marriage as the affirmation of a romantic relationship that may or may not involve parenthood.
Confucius ties marriage to social obligations, and he's a wee bit patriarchal. But Confucius's entire take on religion seems to be: it's good to perform the rites to keep order, but who really knows if there's anything to it. Confucius lived during a turbulent time and mainly wanted to understand how orderly societies function. If you believe, as I do, that sanctioning familial relationships is probably good for social stability in the long run, then the end result of all marriages is to increase order. In that regard, Confucianism, if not Confucius, would seem to be compatible with gay marriage.