They Confirmed Stewie's Not a Baby

Stewie's extraordinary intelligence is explored in an episode of Family Guy where he and Brian accidentally trigger the Big Bang when warping outside of time and space.

The explosion caused by Stewie's return warp is revealed to be the Big Bang, leading to a chain of events affecting Stewie's existence and the universe's creation.

Stewie's half-brother, Nemesis Bertram, attempts to erase their ancestor, Leonardo da Vinci, to prevent Stewie's birth, causing reality to erode until a solution is found to preserve Stewie's existence.

Stewie comes up with a clever plan to ensure his survival by sending Brian to the future, preserving his DNA in Da Vinci's girlfriend, and freezing himself for centuries, ultimately securing his existence.

Stewie's intelligence stems from the universe bending to ensure his existence, manipulating probabilities and orchestrating events to fulfill Stewie's role as a central character in the show.

Stewie's genetic paradox and role as his own progenitor reveal the intricate orchestration of his bloodline and existence, leading to his exceptional intelligence and unique characteristics.

The universe's insistence on Stewie's existence and manipulation of time rules to ensure his survival, as reflected in various episodes and interactions with characters like Penelope and Susie Swanson.

Rupert, Stewie's imaginary friend, is believed to be the universe's way of communicating with Stewie's subconscious, guiding him and serving as a reflection of his deeper self.