I have seen suggestions before that both Sheldon and Brennan are autistic but never as sophisticated as this and never covering the ramifications of them existing without a diagnosis. Very interesting.

These shows are on the old side now, and while autism was certainly known then, not to the extent that it is now. I think that when the people responsible for the characters insist they weren't autistic, they mean that they didn't realize while they were creating them that they were writing autistic characters. It wasn't their intent. They may not have even felt they were knowledgeable enough about autism to write an autistic character. They may have just wrote what they wrote and Sheldon and Brennan, in particular, evolved as they evolved. As a writer, though not for TV, I can imagine that happening.