Today, and ever after, any adult couple in Washington State can get a marriage license, without the need for government approval of their gender combination. This is a happy thing; I personally know several gay couples raising good families, and it's good for everyone that they have the same rights and responsibilities under a marriage license as everyone else.
The arguments against lost, because they are basically "Euw Ick!". But when you think about it, wasn't the prior situation even creepier? You had to prove to the satisfaction of a government clerk that you had the approved set of genetalia! What if they insisted on a "pants check"? Really, some things are private and nobody's business but your own, and you're spouse's.
Change can be hard, and I have to be honest. As a kind I was kind of squicked out by the idea of gay sex, but I had a lucky experience: when I was in the seminary, one of my best friends told me he was gay, in a very non-threatening way. I had to choose whether to stick with my prejudices or stick with my friend, and it wasn't that hard to stick with my friend. We are still friends today, and he's happily married to a guy, having been together for over 25 years (...longer than any of my marriages!) and raised a family quite successfully (although, not having raised a family myself, I don't consider kids to be the only reason to be married.)
If you're into religious argument, Genesis 2:18 reads:
"And the LORD God said, It is not good that the man should be alone; I will make him a helper suitable for him."...and we now know that some men were made by God that another man is that "helper suitable for him", and some women were made by God so that another woman is that "helper suitable". It is not for us to question the way God made them, nor to build barriers in law against God's clear command. There's more on this at No Father, The Gay Sky Isn't Falling.
For everyone else, if the thought of gay sex squicks you out, there's a simple solution: think about something else! What are you doing fantasizing about what your neighbors are doing anyway, you dirty dog!
This is a happy day for so many people, including myself, that we have a new burst of freedom in our state.