A claim that if true just makes your opposition to gay marriage more jarring because their opposition has the benefit of making sense.
So you accept religious opposition to gay marriage as a valid reason?
The only valid opposition to gay marriage is opposition to the archaic construct in its entirety. Anything else is recycling engrained dogma or bigotry.
I simply believe that marriage is a traditional institution which should not be sullied through arbitrary redefinition. I like the homosexuals and I have homosexual friends. But I do not support them having the ability to enter matrimony.
Maintaining a tradition for the sake of the tradition is the worst reason to do so. All traditions of any kind should always be under a lens of strict scrutiny, and be replaced, modified, or altogether removed if it becomes inadequate, outdated or inegalitarian.