When The Simpsons graduated from a sketch on The Tracey Ullman Show to a full-length standalone series, Homer was 34 years old, according to the January 1991 episode "The Way We Was." Plus, the episode "Duffless" says Homer's birthday is May 12. So if we do a little bit of math, that means Homer was born in 1956.

He then aged at a normal chronological rate, at least for a while, because in the late 1992 episode "Lisa the Beauty Queen," he's 36. After that, Homer's aging process slows down considerably. Four years after "Lisa the Beauty Queen," in the 1996 episode "The Homer They Fall," he's still in his late 30s. Two years after that (in 1998's "The Wizard of Evergreen Terrace"), he has a midlife crisis when he realizes that at age 38.1, he's halfway to the male lifespan of 76.2. Homer finally hits the big 4-0 in the episode "Springfield Up," which aired nearly nine years after the episode where he freaked out about being 38.1.

Because Homer's age stays in the same roughly five-year period over the course of 30-plus seasons of television, it gives writers the ability to play fast and loose with his actual age, as well as the opportunity to revise his backstory every few years. In various flashback episodes, Homer has been a boy, teenager, or young man in every decade from the '60s onward.