Subverted: At first Bob thinks that there's some special requirement to wield the Sword of Plot Advancement, but it turns out it's just too heavy for anyone else.
Double Subverted: And then it turns out that somebody else who is not of the blood but has his strength can't wield it.
Parodied: Pulling the newly forged Sword of Plot Advancement out from his magical fires of creation, the wizard declared that only a man or woman born at anytime on any day of any year may wield the sword. Provided that they have hands which can hold the sword's hilt.
Alice: "So only a man may use the Sword of Plot Advancement? Typical. This is sexist and old-fashioned." Bob: "Well, yeah, Alice. It's a magical sword forged in an era where men were knights and women were damsels." Alice: "I wouldn't expect you to understand, Bob."