You may be referring to When You Wish Upon a Weinstein
Season Nine|Episode Four Halloween on Spooner Street
Wasted Talent
Leggo My Meg-O
Sounds like you're referring to the sensational episode 'Road to the Multiverse', in which Brian and Stewie visit one of many universes where humans are pets and dogs are owners. They visit the Griffins and obviously Peter, Lois, Stewie, Meg and Chris are dogs and Brian is a human.
that episode is the feature length episode of movie called "Stevie Griffin, an untold story". . . I think. set in the future megs had sex change and calls herself , , or himself Ron.
meg and stewie (family guy may deny this) were based off of Meg and Charels Wallace from A Wrinkle in Time. The daughter thinks she's ugly and etc., and the son is a genius. Look it up. (not the movie- the movie was bad)-- It should be noted that the above answer is opinion based only. There is no solid evidence, i.e. interviews with the Seth MacFarlane or cast, that proves this. After all, in Stewie's case, Seth has stated Stewie was based on British actor Rex Harrison.
They appear in a fictitious Christmas special, KISS Saves Santa in A Very Special Family Guy Freakin' Christmas and they appear in Road to Europe. Gene Simmons alone appears in Don't Make Me Over
Season 4|Episode 13 Jungle Love
Season 8 | Episode 13: "Go Stewie Go"
Stewie, Meg, Chris, Susie
There's no such episode where Lois does it in front of both Meg & Peter.She is however, caught kissing Meg's boyfriend in Go Stewie Go
Meg is 18Chris is 13 (unofficially 14)Stewie is 1
Eat broccoli, talk/spend time with meg
Lois Griffin from the TV show "Family Guy" has three children: Meg, Chris, and Stewie. Meg is the eldest and the only daughter, while Chris and Stewie are her two sons.
Leggo My Meg-O
Stewie referred to the "Man in White" as the doctor who was present at his birth.Later in the episode after Meg joins the cult the cult leader is dressed in all white robes. He comes to the Griffin's house after Peter brings Meg back home and Stewie sees this as the man in white and he incinerates him with a laser gun.
Bertram was Peter's son & Stewie, Chris & Meg's half-brother... however only Stewie (& Brian) knew he existed and neither Stewie nor Bertram knew they were actually related.
16
Dial Meg for murder, season 8