Season 4 · Episode 22 · First aired 26 March 2006
Sibling Rivalry
Episode 22 of Family Guy season 4 (S04E22), the 72nd Family Guy episode overall. Written by Cherry Chevapravatdumrong and directed by Dan Povenmire. First broadcast on 26 March 2006.
Story
After a pregnancy scare Peter agrees to a vasectomy, first depositing sperm at a bank in case of another child. He knocks over every sample and refills the containers himself. A lesbian couple use one and bear Bertram, Stewie's half-brother from "Emission Impossible". Bertram declares war on Stewie for the playground. An aerial dogfight ends in stalemate, so Bertram uses Stewie's new girlfriend to infect him with chickenpox. Once recovered, Stewie defeats Bertram in a sword fight. He is later seen digging a hole with Christopher Moltisanti, for a tree. Meanwhile Peter loses interest in sex after the operation and Lois turns to food. When Peter mocks her weight she eats more out of spite and becomes obese, which revives their sex life, so Peter feeds her further. Her heart fails during sex; surgeons remove the fat, and Peter is later found kissing it in a cupboard.
Production and reception
- Cherry Chevapravatdumrong wrote the episode and Dan Povenmire directed; Wallace Shawn voiced Bertram. Wikipedia, Sibling Rivalry (Family Guy)
- The producers debated whether to bring back Bertram, who had not appeared for several years. Wikipedia, Sibling Rivalry (Family Guy)
- Alec Sulkin and Alex Borstein wrote the song that follows Lois's negative pregnancy test, and Walter Murphy orchestrated it; the Ice Age producers agreed to the Scrat cameo five days before Ice Age: The Meltdown opened. Wikipedia, Sibling Rivalry (Family Guy)
- Broadcasting standards objected to Peter singing Milkshake naked in a prison cutaway, so he was shown in underpants instead. Wikipedia, Sibling Rivalry (Family Guy)
- The first airing drew 7.95 million viewers, 77th for the week; Bob Sassone of TV Squad reviewed it warmly while Geoffrey D. Roberts of Real Talk Reviews was negative. Wikipedia, Sibling Rivalry (Family Guy)
Voices
| Voice | Characters |
|---|---|
| Seth MacFarlane | Peter Griffin, Brian Griffin, Stewie Griffin |
| Alex Borstein | Lois Griffin, Gym Teacher, Woman in Bed |
| Seth Green | Chris Griffin |
| Mila Kunis | Meg Griffin |
| Randy Crenshaw | Barbershop Quartet Singer #4 |
| Gavin Dunne | Christoper Moltisanti |
| Ralph Garman | Letter A |
| Mike Henry | Cleveland Brown |
| Bob Joyce | Barbershop Quartet Singer #1 |
| Jon Joyce | Barbershop Quartet Singer #2 |
Principal voice credits as recorded by IMDb, which lists up to ten credits per episode, so recurring characters can be missing here. Guest voices below come from Wikipedia and TVmaze.
Guest voices
- Randy Crenshaw as Barbershop Quartet Member
- Gavin Dunne as Christoper Moltisanti
- Bob Joyce as Barbershop Quartet Member
- John Joyce as Barbershop Quartet Member
- Phil LaMarr as Morgan Freeman, Man
- Rick Logan as Barbershop Quartet Member
- Wallace Shawn as Bertram
- Tara Strong as Boy/Stewie's Girlfriend
- Nicole Sullivan as Nurse at Sperm Bank, Receptionist
- Wally Wingert as B.C. #2, U
- Chris Wedge as Scrat (uncredited)
- Patrick Warburton as Joe Swanson
- Ralph Garman as Caveman #1
- Alec Sulkin as Tony Danza
- Danny Smith as A
Season 4: episode 22 of 30
- E1North by North Quahog
- E2Fast Times at Buddy Cianci Jr. High
- E3Blind Ambition
- E4Don't Make Me Over
- E5The Cleveland–Loretta Quagmire
- E6Petarded
- E7Brian the Bachelor
- E88 Simple Rules for Buying My Teenage Daughter
- E9Breaking Out Is Hard to Do
- E10Model Misbehavior
- E11Peter's Got Woods
- E12Perfect Castaway
- E13Jungle Love
- E14PTV
- E15Brian Goes Back to College
- E16The Courtship of Stewie's Father
- E17The Fat Guy Strangler
- E18The Father, the Son, and the Holy Fonz
- E19Brian Sings and Swings
- E20Patriot Games
- E21I Take Thee Quagmire
- E22Sibling RivalryYou are here
- E23Deep Throats
- E24Peterotica
- E25You May Now Kiss the... Uh... Guy Who Receives
- E26Petergeist
- E27The Griffin Family History
- E28Stewie B. Goode
- E29Bango Was His Name, Oh!
- E30Stu and Stewie's Excellent Adventure
SourceFacts from Wikipedia: Family Guy season 4 and the episode's article (CC BY-SA 4.0). Spotted an error? See corrections.
Provenance
Facts only- Data refreshed
- 6 September 2026
- Verification
- Checked against Wikidata and IMDb: title, date, numbering and credits agree
- Licence
- Facts are not copyrightable. Source text on Wikipedia is CC BY-SA 4.0; Wikidata is CC0; IMDb data is used for verification under its non-commercial terms.
- Note
- The story summary and notes were written for this site from the sources listed, by Claude in Claude Code on 2026-09-08, awaiting editorial review. Facts only; no dialogue is reproduced. Voice credits: Information courtesy of IMDb (https://www.imdb.com). Used with permission. Guest cast data from TVmaze (https://www.tvmaze.com), CC BY-SA.