Considering that only 10 percent or less of the population is gay, I still don't see how it's going to affect those who are straight and married.
And..................as far as adoption, I don't think that the adoption agency is going to have couples competing for the same child. I was in a foster program (where you can be moved from family to family) for around 5 years, and there was NEVER more than one couple interested in having me in their family.
And..................as far as people getting together just for the benefits? Saw it happen on a regular basis while in the Navy, because some of the lower ranks (E-1 to E-4) would get married simply because they didn't want to live in the barracks and wanted a house in town. E-4 and below (at most commands) have to get special permission to live off base, but if they marry, they don't, and they draw BAQ and VHA.
Matter of fact, there was a lesbian that got married to a gay man (happened during my second tour), and although we couldn't prove they were getting married just for the benefits, many had their doubts since they each had their own room at their house. And.............it also provided a pretty good cover so they didn't get kicked out for being gay.
But like I said..................gay marriage isn't going to affect straight marriage in the slightest. It's just more Christian bigotry against those who are different from them and don't hold their archaic beliefs.