The British tabs are abuzz because a genealogist discovered that young Prince William is a distant relation to his long-time girlfriend, Kate Middleton. According to the Daily Mail, "The man who links William and Kate as kith and kin is Sir Thomas Leighton, an Elizabethan soldier, diplomat and, for 40 years, the cut-throat Governor of Guernsey." This connection makes them 12th cousins, and if you've seen any photos of the extended Royal Family, it shouldn't shock you to find out that there's been some unfortunate inbreeding going on. However, it's not just the Royals and archetypal hillbillies who are intermingling. . . .
There are many examples of incestuous (and just sort of creepy, borderline-incestuous) pairings on this side of the pond:
The former mayor of New York married Peruggi, thinking she was his third cousin. They later discovered they were actually second cousins. This oversight never could've happened in my meddling family, but that's the story they're sticking to and besides, he's had a few marriages since then.
In her memoir, The Kiss, Harrison details the love affair (her words, not mine), she had with her dad. She was a consenting adult when the affair happened and he hadn't been around much when she was growing up, but, uh, yuck.