Sitcom writers have a tough job. Trying to produce a "mini-script" every week for 26 or more weeks to make one season of television is difficult. When a show becomes popular and gets picked up for more seasons, the task of continuity in writing becomes even tougher. Here are a handful of the more memorable inconsistencies in some of our favorite sitcoms.

Gilbert, Whitey & The Beaver

Gilbert Who?

A true family classic, "Leave It To Beaver" is an icon in television history. Clean teens, 1950's American dream living and a mom who wears pearls and heels to clean the house. What more could anyone ask for in a television program? But The Beaver's poor friend Gilbert, played by Stephen Talbot, suffered from an identity crisis through the six-39 episode seasons of the show. His name was given as Gilbert Bates, then Gilbert Gates, then for a few episodes he was inexplicably called Gilbert Harrison, then it was back to Gilbert Bates. So what was Gilbert's last name? According to the program's listing at, Bates is Gilbert's "official" last name. They do have a disclaimer admitting that he is "also known as Gilbert Gates" but they don't mention the Harrison blunder at all.

So what is to blame for this name gaffe? Well, during the shows 234 episodes, a whopping 27 writers are given credit as scriptwriters, although the shows two original writers, Joe Connelly and Bob Mosher, wrote the bulk of the episodes. Even Hugh Beaumont (Mr. Cleaver) showed his writing chops on an episode.  As for you Gilbert, or should I say Mr. Bates, er...Gates...or is it Harrison? Well, whatever your name is, we still love you in syndication.

The Cosby's

The Cosby Show is a wildly popular sitcom of the 80's. In fact, it's the show that brought "must see TV" (and an enormous ratings share) back to NBC. But the writers made a few errors throughout the series' 201 episodes. The following are some of the series' most memorable goofs.

The Fifth Cosby Kid?

In the first season of the show, Cliff and Clair despair often of the behavior of their FOUR children. Yet in season two we are introduced to Sondra (actress Sabrina Le Beauf), Princeton student and the oldest of the Cosby kids. Sondra would be a semi-recurring character for the remainder of the show, along with her befuddled boyfriend/husband Elvin Tibideaux, played by Geoffrey Owens.

Paging Dr. Clifford/Heathcliff Huxtable

Dr. Cliff Huxtable, played by the beloved Bill Cosby, had a bit of an identity crisis à la Gilbert Bates. In the first season of the show, a plaque on the wall outside his office entrance read "Dr. Clifford Huxtable". Somehow, through the program's evolution, Clifford became "Heathcliff". Why the name change? Nobody knows; apparently someone on the writing staff thought that Heathcliff sounded like a name more befitting a doctor.

Does Denise Know Sondra Dated Her Husband?

Lt. Martin Kendall, played by Joseph C. Phillips,  is a new character introduced in the first episode of the sixth season of the Cosby saga. Denise brings him home from Africa and presents him as her new husband, much to the family's surprise. But how can this be, when the family has already met him? In episode four of the second season, Sondra and her beau Elvin have broken up, yet again. Sondra's friends introduce her to...Lt. Martin Kendall. Only in THIS episode his name is David, and he's a college student friend of a friend who Cliff takes a shine to, as he has repeatedly shown his disdain for Elvin.

This type of error in continuity really isn't the fault of the writers, but a casting gaffe. However, it is a noticeable error and one that's amusing to boot.

The Connor Family

Darlene's Boyfriend is...Kevin Healey?

"Roseanne" was undoubtedly one of the most true-to-life sitcoms, and certainly the most popular of the early 90's. But even the great Ms. Barr's show wasn't without its writing flubs. A favorite is a "blink-and-you'll-miss-it" reference at the end of one episode that will come back to haunt the show's writers for many years in syndication.

The character of Darlene Connor, middle daughter of Dan and Roseanne and brilliantly played by Sarah Gilbert, is a mess. She's rebellious, dark, moody and doesn't live up to her academic potential. But the Connors' have their hands full dealing with the Romeo and Juliet relationship between oldest daughter Becky (Lecy Goranson) and her punk boyfriend Mark Healey (the late Glen Quinn). So what better way to shake things up than to introduce David Healey, Mark's polar-opposite younger brother, as Darlene's love interest. Here's the problem though: when "David" (the amazing Johnny Galecki) is first introduced on the show, during one of the series' infamous "final credit" snippets, he tells Roseanne his name is Kevin, Mark's little brother. So why the name change? One can only assume that one of the staggering 66 writers didn't do his or her homework.

That '70's Show

Disappearing Characters

Some sitcoms make the error of "introducing" a character in the pilot, or even in a few episodes, then that person is never seen again. The iconic 70's sitcom "Happy Days" had one such character. In the first season, we meet Chuck Cunningham, Richie and Joanie's older brother. One day Chuck went out to play basketball...and never returned. In fact, Chuck was so completely gone that in a later season, Howard Cunningham (Tom Bosley) declares that he has "the best two kids in the world". Poor Chuck. We can only assume that his exile from the family had something to do with his father's lack of acknowledgement.

A more recent sitcom, "That '70's Show" also has a character with a lost sibling. Donna Pinciotti, played with great elan by Laura Prepon, apparently had a little sister named Tina. We meet Tina very briefly in the pilot episode, then Tina simply disappears. She is humorously mentioned on a later episode as part of a "Soap"-like voiceover, proving the show's creators have a sense of humor about their mistakes.