<P> Despite the animation and fantasy setting, the series was initially aimed at adult audiences, which was reflected in the comedy writing, which, as noted, resembled the average primetime sitcoms of the era, with the usual family issues resolved with a laugh at the end of each episode, as well as the inclusion of a laugh track . Hanna and Barbera hired many writers from the world of live action, including two of Jackie Gleason's writers, Herbert Finn and Sydney Zelinka, as well as relative newcomer Joanna Lee while still using traditional animation story men such as Warren Foster and Michael Maltese . </P> <P> The Flintstones premiered on September 30, 1960, at 8: 30 pm, and quickly became a hit . It was the first American animated show to depict two people of the opposite sex (Fred and Wilma; Barney and Betty) sleeping together in one bed, although Fred and Wilma are sometimes depicted as sleeping in separate beds . For comparison, the first live - action depiction of this in American TV history was in television's first - ever sitcom: 1947's Mary Kay and Johnny . </P> <P> The first two seasons were co-sponsored by Winston cigarettes and the characters appeared in several black - and - white television commercials for Winston (dictated by the custom, at that time, that the star (s) of a TV series often "pitched" their sponsor's product in an "integrated commercial" at the end of the episode). </P> <P> During the third season, Hanna and Barbera decided that Fred and Wilma should have a baby . Originally, Hanna and Barbera intended for the Flintstone family to have a boy, the head of the marketing department convinced them to change it to a girl since "girl dolls sell a lot better than boy dolls". Although most Flintstones episodes were stand - alone storylines, Hanna - Barbera created a story arc surrounding the birth of Pebbles . Beginning with the episode "The Surprise", aired midway through the third season (January 25, 1963), in which Wilma reveals her pregnancy to Fred, the arc continued through the time leading up to Pebbles' birth in the episode "Dress Rehearsal" (February 22, 1963), and then continued with several episodes showing Fred and Wilma adjusting to the world of parenthood . Around this time, Winston pulled out their sponsorship and Welch's (grape juice and grape jellies) became the primary sponsor . The integrated commercials for Welch's products feature Pebbles asking for grape juice in her toddler dialect, and Fred explaining to Pebbles Welch's unique process for making the jelly, compared to the competition . Welch's also produced a line of grape jelly packaged in jars which were reusable as drinking glasses, with painted scenes featuring the Flintstones and characters from the show . In Australia, the Nine Network ran a "Name the Flintstones' baby" competition during the' pregnancy' episodes--few Australian viewers were expected to have a U.S. connection giving them information about past Flintstone episodes . </P>

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