After dinner with Emily and Richard, Rory and Lorelei are talking about the dinner, Rory is mad at Richard and says "what's wrong with that man?" And Lorelei says "that is about a hundred years of inbreeding".
But when Richard's mom, gran, dies and Emily and Lorelei are going through all her things, Lorelei is shocked to learn that the Gilmores would marry other Gilmores, because they considered their bloodline superior.