Marge gets the car of her dreams after her station wagon falls into a sinkhole — but soon she becomes angry over the decision, as it clashes with her deep-seated desire to have another baby. Meanwhile, Bart and his friends spy on Lisa when Lisa begins taking private after-school lessons from one of Principal Skinner's rivals.
Tropes:
- Chekhov's Boomerang: Trying for a fourth child causes Homer and Marge to finally discover that Homer is sterile due to radiation exposure at the power plant, which the viewer found out back in season 3 when Burns turned it up in a company physical before fixing things so that the family could never sue if they found out. (Though they appeared to know in Season 11's "Eight Misbehavin'.")
- Continuity Nod: At the end of the episode, the Simpsons watch a 3D re-release of The Itchy & Scratchy Movie from the episode of the same name.
- Credits Gag: The entirety of credits are in a cursive font, alluding to how Lisa was learning cursive.
- Drive-In Theater: The Simpsons go to one at the end of the episode, in order to view a 3D version of The Itchy and Scratchy Movie.
- Foreshadowing: When Marge first gets her new car, she complains about how small it is. Later, Homer makes a comment how there is just enough room in the car for the whole family, which leads to Marge griping about the smell. Soon, she realizes with Homer's help that she wants more kids.
- Kitchen Sink Included: A news report about the sinkhole has the caption "Everything and the kitchen sinks".
- Pun: Everything and the kitchen sinks.
- Series Continuity Error:
- The Simpson family watch The Itchy & Scratchy Movie from "Itchy and Scratchy: the Movie", even though Bart was banned from watching it and it was heavily implied he never got to see it until he became Chief Justice of the Supreme Court years later.
- Homer and Marge find out for the first time that Homer is sterile due to radiation exposure, though they discussed the fact in "Eight Misbehavin'."
- How was Bart able to read Lisa's cursive sentences when it was previously established that he couldn't read cursive at all?
- Strong Family Resemblance: All the babies born from Homer's sperm look nearly identical to him and even say "D'oh!"
- Unusually Uninteresting Sight: A brief gag reveals that Jeff Gordon now lives in Springfield and Moe has become used to his presence.
- What Happened to the Mouse?: Marge's station wagon got stuck and buried for the rest of the episode, but she gets it back in the next episode.
- Wingding Eyes: When a sample of Homer's sperm is seen through a microscope, Homer says he sees two "X" instead of eyes.
- Writing Lines: As a lampshade to the chalkboard gag, Bart tells Lisa he writes lines on the chalkboard everyday and needs new ideas.
