As a philosopher, I must state that gay marriage is unnatural.
Of course, no one could argue that "gay marriage" is found in nature, so as a philologist, again I honestly state that it is unnatural.
When I say that "Gay marriage is unnatural.", as I am apt to do in my private life, I hope that astute listeners will
1. realize I speak truthfully
2. and they should realize that all marriage is unnatural.
Perhaps the unnaturalness of marriage is why Nietzsche said that marriage should be a contract for a defined period of time.
If my listeners are not astute to follow the my logic, I will find them the amusing creatures that they are.