A Family Guy fan theory reveals the dark origin of Brian Griffin, and it's both intriguing and entirely plausible within the show's own story. Family Guy started out as a relatively unremarkable animated comedy with a heavy reliance on cutaway gags, but after finding its feet it quickly became one of the most successful animated TV shows of all time. Over the years, Family Guy's central characters have evolved, changing with the times in order to remain relevant to modern culture.
One of Family Guy's most grounded characters is actually not human at all. Brian Griffin the only non-human member of the Griffin family, but his personality is no less human than any other character on the show. Based loosely on Family Guy creator Seth MacFarlane, Brian's distinctly human nature is at odds with his canine appearance. Though the show often plays this up for comedic purposes, it's deliberately kept as one of Family Guy's biggest mysteries.
However, one theory posted to Reddit suggests a clear in-universe explanation for Brian's apparent humanity. According to the theorist, Brian is most likely a CIA genetic experiment, and this explains why his personality and mind are those of a human while his body is that of a dog. The theory draws on evidence from Family Guy and American Dad!, making it surprisingly convincing.
How Brian Griffin (And Others) Are Part Of A CIA Experiment
From Family Guy's very beginnings, Brian has been a significant part of the show. His character has actually changed relatively little over the course of Family Guy's run: Brian has always been a talking dog living in a human world, and it's rarely ever brought up in service of anything other than jokes at his expense. However, according to the theory, the likelihood is that Brian actually has a human mind somehow implanted into the body of a dog. As Family Guy often depicts more run-of-the-mill animals, proving that they aren't all as loquacious as Brian, it's clear that there's an in-universe reason for some animals acting far more human than others.
The answers spill over into Family Guy's sister show, American Dad!. The two shows take place in the same universe, and American Dad! also features a number of talking animal characters, also these characters are confirmed as being the result of CIA experiments. Further proof that Brian's genes have been tampered with comes from an apparent plot hole in which Brian's son Dylan is human - if Brian procreated from a canine body, his children should also be (at least partly) canine. If Brian is indeed the product of a genetic experiment, this could potentially explain how his biological child could still be born human, as the pseudo-science behind one could be used to facilitate the other.
Family Guy's Talking Animals Enjoy Human Lives
An important part of the theory is just how human Brian really is. He rarely behaves like a dog, and is instead regularly shown pursuing his own dreams and aspirations. This extends to almost every facet of Brian's life - he's had numerous careers, and is shown to be capable of particularly complex existential thought, making his mind seem decidedly more human than canine. Brian even understands the nature of time travel, as he and Stewie regularly end up tampering with the very fabric of reality. In many ways, Brian Griffin's life - occasionally outlandish though it may be - is thoroughly human.
The same can be said for other talking animals in the Family Guy universe. There's Ernie the Giant Chicken, an anthropomorphic chicken who is shown to be married and capable of carrying on a long-standing feud with Peter that regularly devolves into physical violence. The Cleveland Show's Tim and Ariana are a married couple of bears who enjoy a normal human life. Brian is briefly replaced by other talking dogs, named Vinny and New Brian respectively. There's also Meowsy McDermott, a lawyer smart enough to keep Family Guy characters out of jail who just happens to be a cat. It's established that some of the animals of the Family Guy universe are capable of living normal human lives, and this is rarely questioned by any of the show's human characters.
Family Guy Glosses Over The Potential Societal Concerns
The apparent integration of humans with talking animals in Family Guy's society is relatively smooth. In many episodes, such as Family Guy season 1, episode 8, "Brian Griffin: Portrait of a Dog," animal characters are treated as second-class citizens (allowing the episode to lightly parody civil rights dramas), so it's clear that the show's universe has had its issues with reconciling talking animals with its humans. However, for the most part, Family Guy glosses over the more complex societal concerns.
Other than Family Guy's Quagmire hating Brian, most characters are happy to accept his place in their lives. This even extends to interspecies dating, as Brian is seen on numerous occasions to be romantically involved with human women. Though these relationships are sometimes implied to be relatively taboo, there is a general acceptance of the interspecies dating that takes place within the show, which seems to further evidence how normal human-acting animals are within Family Guy's world.
How American Dad! Proves The Theory
Perhaps the best piece of evidence for the Family Guy theory about Brian's origin as a genetic experiment actually comes from one of Seth MacFarlane's other shows, American Dad! A number of 's characters are also talking animals: Klaus, the Smith family's goldfish, and Reggie, a colleague of Stan's who also happens to be a koala. Within American Dad!'s story, these characters were once human, but had their minds transferred into their respective animal bodies. How this is achieved is shown in American Dad! season 5, episode 4, "Brains, Brains and Automobiles," in which Stan uses the CIA's mind transfer technology. This same technology (or some adapted form of it) could plausibly be behind Brian's human traits.
In line with the theory, had the CIA used this technology to put the mind of a young child into the mind of a puppy, the result would almost exactly match up with Brian's origin. By using the young mind of Family Guy's Brian as a replacement for that of a puppy, Brian wouldn't have ever known another body. Though this seems distinctly unethical, the widespread nature of talking animals living human lives makes it relatively commonplace within Family Guy and American Dad!'s universe, which only seems to make the theory all the more plausible.