IT'S the late 1960s, and, flushed with the success of Gilligan's Island, producer Sherwood Schwartz decides to take a punt.

Struck by a news article reporting that nearly half of all married couples in the US have a child from a previous marriage, Schwartz hawks his new idea for a sitcom around to a few networks reluctant to embrace the idea of an "unconventional" family. It finally gets up following the success of the Lucille Ball and Henry Fonda movie Yours, Mine and Ours.

By 1969, series one of The Brady Bunch was being screened across the US (five were made), making it one of the first programs featuring blended families to feature on the small screen.

The show featured the trials and tribulations of Mike Brady, the handsome widower with three sons, who marries Carol, the mother of three very lovely golden-haired girls with curls.

But by 1970, with oral contraception readily available, it was no longer the norm to have six children in a family. It was also highly unusual for dad to work from home and difficult for most children to imagine what it would be like to live in a two-storey architect-designed house in Santa Monica with a housekeeper.

So for many viewers it was a window into another world. Forty years later it still is for the same reasons.

The Brady Bunch was also a perfect and safe world where everyone knew their place and there was a place for everyone.

Moms were moms and were content to stay at home curling their eyelashes. Dads were dads doing whatever it was that dads were supposed to do as the patriarch of the family.

Children were seen and not heard and dutifully obeyed their parents, teachers and the law. Ah, those were the days.

No wonder the producers had to devise form letters to deal with correspondence from children who said they wanted to run away to live with the Bradys. I'm just thrilled our letters from Grade 3P, Roslyn Primary School 1973, got there.

Fast forward 40 years and The Brady Bunch has been repeated countless times, spanned several generations and has also spawned some truly cringe-worthy specials (cranked up to keep pace with the new family on the block, The Partridge Family, such as The Brady Bunch Movie, A Very Brady Christmas, Groovin' With the Bradys and, believe it or not, My Fair Brady).

Clearly American viewers are very forgiving. They've even forgiven the scandals surrounding the show, such as Carol's off-screen liaison with Greg, and Mike, apparently being picked up for loitering somewhere near Sunset Boulevard at the end of the fifth series.

In fact, despite such glitches, such is the program's enduring popularity that in the US, The Brady Bunch has apparently featured on television daily from 1969- 2007, and that's despite it never even making the ratings' top 10.

In Australia a new audience has been introduced to the show through DVD rather than television. Major retailers tell me sales of The Brady Bunch have been steady since it was first released in Australia a year ago and that sales of retro television programs consistently do well across the board.

So, as we eagerly await, with the same anticipation as Alice's pot roast, the delivery of series two to five from Amazon, I've been quizzing my two-person focus group about why they are content to watch The Brady Bunch over and over despite them getting all hot under the collar about issues such as wives and children as chattels; blatant sexism and slave labour ... just like Marcia Brady did in the episode where she discovers women's lib and burns her training bra.

And that's what's so puzzling. The contradiction.

This quaint show from nearly half a century ago seems to be striking a chord with the same audience tuning into The Simpsons; That's So Raven; Hannah Montana or the Suite Life of Zac and Cody.

In these shows the children with "attitoode" rule the roost; the parents are bumbling inconsequentials and the teenage protagonists have piercings.

Marcia Brady - the prototype babe - would be mincemeat if plopped on set with Raven Symone yet she is still a role model for young girls alongside Miley Cyrus.

Although much of The Brady Bunch belongs in a museum, its enduring appeal demonstrates that adolescent angst is indeed timeless as is schoolyard bullying, peer pressure, sibling rivalry and flunking tests.

Yes, The Brady Bunch may be treacle TV, but it's much easier talking to children about changes in social mores than explaining why a "dangerously thin" teenager with legs thinner than my arms was put through to the finals on Make Me A Supermodel.

Series one and two of The Brady Bunch are available on DVD.