[Iron Munro]

The The “Hapsburg lip” is a well-known hereditary feature.

That explains it.

Habsburg Jaw and Other Royal Inbreeding Deformities

[MUDDOG]

Since we can't get a DNA test, maybe there's some kind of facial recognition program that flags hereditary similarities.

You'd think it would be possible to program something like that, given the knowledge that's been accumulated about hereditary features.

Of course, the program wouldn't be determinative, but it'd be like those literary-style analyzing computer programs that identified who the anonymous authors of the Federalist Papers really were, and identified Joe Klein as the "Anonymous" author of "Primary Colors" (and Ayers on "Dreams").

I actually read about these literary analyzing programs in a Springer-Verlag book on statistics.