Originally aired: December 13, 2009
Jealous of the sisterly bond between Lisa and Maggie, Bart sets out to get a little brother — first by making Homer and Marge have sex, then by adopting an orphan.
- Brick Joke / Funny Background Event: Homer's scene with the dynamite ends in the next scene with Bart and the social worker.
- Call-Back: Nelson and the Tac-Tics
- Continuity Nod: This isn't the first time Bart replaced a woman's birth control pills with Tic-Tacs (only they're called "Tac-Tics" here).
- Dramatic Irony: Bart's illegal brother Charlie ends up suffering a much worse fate as the brother to his eventual adopted six sisters with No Sense of Personal Space, after Bart previously feared having a third sister.
- Imagine Spot: Bart has one about how his future will be if his parents have a third daughter.
- Outnumbered Sibling/Reality Ensues/Siblings Wanted: Bart starts feeling the first trope in this episode, but when he tries convincing his parents to have another kid and explains to Marge why he wants a brother so badly, his mom (though she can understand why Bart feels that way) explains that she and Homer are fine with just three kids. Marge also points out that even if she and Homer do ever end up having another baby, it might not be a boy—in fact, a potential fourth child very well could end up being another girl, resulting in Bart having three sisters (this is what ultimately leads to the third trope, for when Bart tries adopting an orphan boy as his brother).
- Later, Charlie (the orphan acting as Bart's "brother") is adopted by a couple with six daughters.
- Shout-Out: The scene of Bart telling his friends about his baby brother dilemma looks and is "animated" like South Park.