Answer: God doesnt have a birth certificate, either.
Curiouser, and curiouser.
After telling this joke, he goes on to say that he's "working on something very important" ?
Man, oh man. All I can say, is that he's definitely got my attention. Sure hope it turns out to be something of real import.
Then again, this is Rush we're talking about. Rush wouldn't put out that sort of teaser, unless he feels he's got something truly major in the oven.
He had to be doing something along those lines or else why bring up the God BC joke first?