The Simpsons: 20 Annoying Mistakes You Didn't Notice

12. Homer Is Firing Blanks... Sometimes

As part of the side-effects of his working at the Nuclear Power Plant, Homer is revealed to be sterile, as established in season 3 in "Brother, Can You Spare Two Dimes," and has been for some time - at least since Bart was born. But in "O Brother, Where Bart Thou?" a full 18 seasons later, it is revealed that Marge is taking birth control pills, which Bart swaps with Tic Tacs in an attempt to get a little brother. So why exactly is Marge still taking birth control pills if her husband is firing blanks? Is she really that forgetful?

11. The Spucklers

What began as an opportunity for throw-away red-neck jokes has seen Cletus Spuckler and his family given more prominence as the show has gone on, but there are some serious inconsistencies. The Spucklers weren't even called the Spucklers to begin with, as Cletus' name was initially given as Cletus Del Roy, but it's the lineage of the family that is the most confused. When Homer was ordained as an Internet minister, he was about to marry Cletus and Brandine, and remarked "Wait a minute... are you two brother and sister?" to which Brandine replied, "We's all kindsa thangs, which is something of an understatement. In "The Italian Bob," Brandine remarked to Cletus "Yer tha best husband, brother and son I ever did have," despite early episodes establishing a Spuckler family member called Maw. And then in "Little Big Girl," one of the Spuckler sons draws a family tree that suggests that Brandine is the child of Cletus and an alien. Additionally, in one episode it is revealed that the Spucklers have 51 children, but other episodes throughout the show's history have suggested numbers as diverse as 19, 44, 31 and 39, including a sheep and a walking hot dog. The short answer, it seems, is that nobody really knows.

10. Ned Flanders Is One Of The Oldest Men In Springfield, Except When He's Not

How old is Ned Flanders? In "Hurricane Neddy", Ned was sent for treatment with Dr. Foster 30 years ago for anger aversion that lead to his speech eccentricities (despite the fact that all of his male relatives apparently share a genetic predisposition to the same quirk), when Ned was a child, making him 34 or so, assuming that he was 4 when he was treated. But in "Viva Ned Flanders", he reveals that he is 60 years old, and when Mr Burns is awarded the Oldest Living Springfieldian award, Ned remains standing with all other residents who are older than 60.