So they'll get tax benefits now? Isn't that the only actual benefit of getting married and getting a marriage certificate?

On a side note all the states in the US that are the most vehemently opposed to gay marriages are the ones with the highest levels of incestuality and beastiality. But they don't get tax benefits so it's alright.

There is direct proof that children can't give consent. There is direct proof that animals can't give consent. That is why those things will not get legalized.