In Britain, there's a small flap over David Cameron's commitment to recognizing married couples in the tax system, something the UK currently, and bizarrely, doesn't do. The trouble is its cost in a period of terrible public finances after years of Labour over-spending. Cameron is going to have to find a more affordable way to fulfill his promise. But note that Cameron, by backing civil partnerships for gays, but not marriage, would not extend these benefits to gay couples, as if the state does not have just as big an interest in supporting gay families as straight ones.
Even when a separate system for gay couples is deemed equal, it almost never is. Only marriage works. Only marriage is equality.