Rachael suggests that Krendler is not talking about her virginity but rather her Electra complex. In other words, he is saying is that Clarice is too old to be screwing her daddy. Another dig at her humble origins. [Thanks Rachael.]
[Contributed by lrr3]
Lecter watches a film, A Brief History of Time, which he's seen many times before, running it backwards over the part where the teacup smashes on the floor. This is reminiscent of Jame Gumb watching films of his mother and Dolarhyde reviewing his many films.
Stephen Hawking is on another plane entirely from the rest of us. Similar things are said about Hannibal. If ever there was a man to match wits with Hannibal, Stephen Hawking might just fit the bill. Interestingly, Mason Verger seems to have a few of Stephen Hawking's traits - immobility and voice, perhaps. [Thanks to Gary Larson]