Chaotic, I have to disagree. Of course it is a right ceremonially. Of course any couples can declare themselves married and live together if they want. But the underlying issue is the government's obligation to recognise and grant a licence to the people. If the government must give a licence to recognise a couple, then marriage accordingly is not a right. The government's involvement and obligation is the subject. Oh, by the way, if it were a right, then the government would have to recognise even two consenting adult relatives that chose to be engaged maritally. If the government's concern were that they would risk the lives of children they brought into the world, then they could have the couples commit to sterilisation. Hence, they won't be able to have any kids. Or alternatively they can oblige the couples to abort the baby if medical check up indicates that the baby would be deformed or mentally retarded. So back to my statement that it's not a right. . . .
Why do people need the licence of the government to feel satisfied or feel committed to each other? So you want taxes cut, property and any other benefits, but that boundary is no longer individual rights. It is a privilege or a subject of equality in a different sense. And if it's a subject of equality, then it should also stretch to single people, not just homosexuals. Should one be indirectly penalised for failing to officially wed or choosing not to go in the path of wedlock? It's definitely not a subject of natural rights.