This weekend was Pride in San Francisco. In the morning Dan Choi gave a stirring speech (the three words that got him kicked out of the military, he said, were not "I am gay," but "I love you").
Watching the parade I started thinking about the way that "natural" has been used as a rhetorical bludgeon to fight the sort of celebration of difference that I was seeing. Now that we know there are gay dolphins and gay seagulls we should hear a change of tune from the people who argued that homosexuality was bad because it wasn't natural. But of course we won't. In cases like this the natural claim gets grafted on to support the belief - if something is bad it's unnatural.
Often, I think what we are really saying if we say something is unnatural is that it is foreign to our system of beliefs.