@cicerone imposter,
First of all, I would ask you to stay civil and not revert to name calling.
What you have written about incest -- that was the point of my original posting that gay marriage is very different from the heterosexual marriage. Incestous relationships are not allowed because that would cause problems with offsprings. But because there is no problem of incest in same sex relationships, it would be illogical not to allow marriages between close relatives of same sex.
After that, if gay marriages are at same level as heterosexual marriages, it would be discriminatory not to allow marriage between close relatives for heterosexuals as well. That is how it would upend traditional heterosexual marriages.
My point is that gay alliance is very different than a heterosexual marriage. So society should plan on calling gay alliances by a name different from "marriage."