Slay, Monstrobot of the Deep) directed this query at me: "Insane theory to launch a thousand fanfics--Capt Jack Sparrow is an ancestor of Sally Sparrow. Discuss." Well... Other than serving to get two Captain Jacks into the same universe and likely shagging, what can we do with this idea?
I guess it all depends on whether Captain Jack sired any children in wedlock (so they'd have his name). Did he? His only family on record is Captain Edward Teague, his father, which means "Sparrow" isn't even his real name. Sparrow is his pirate name, so he can't have sired a son before the pirate life cast a spell on him. Well he's not dead yet (though he refused immortality, so isn't quite as tough as Harkness). Jack's only really had one love interest that I know of (except the sea) and that's Blackbeard's daughter Anjelica. Do they ever get together and can she forgive him killing her father and leaving her on a deserted island? That would give Sally quite the bloodline! In the next film, he'll apparently become enamored of Barbossa's daughter, Carina. Same deal, really.
Let's say he marries a pirate princess down the line, and that eventually, Sally Sparrow is born from this family, one could indeed launch 1000 fanfics, at least some of them a huge crossover with Captain Avery (The Curse of the Black Spot) and possibly the guys from William Hartnell story, The Smugglers. I'm sure Sally looks as good in pirate drag as Amy did, probably better, with Larry Nightingale as her own personal swabby/Rory. Hey, who left a big cemetery angel in the hold?