Many scientists allege that every seven years each cell in our bodies is replaced by a new one.

Thus, in that time-span we essentially become new people.

Keeping that in mind, it's logical to have five couples of different ages - and not just one -- tell the story of a 50-year marriage.

I DO! I DO! was a two-character musical when first produced in 1966. Mary Martin (a/k/a Nellie Forbush, Peter Pan, and Maria von Trapp) starred with Robert (The Music Man) Preston. They played Michael and Agnes, whom we followed from their marriage in 1900 to their 50th anniversary.

Preston won a Tony and Martin was nominated - but to be honest, she at 53 and he at 48 were too old to start the show as virgin newlyweds. They wouldn't actually be the right ages until Act Two.

With the estimable York Theatre Company marking its own 50^th anniversary, Tom (The Fantasticks) Jones - who'd written the book and lyrics to Harvey Schmidt's music -suggested to producing artistic director Jim Morgan to mount a concert with five age-appropriate couples.

MTI has been licensing I DO! I DO! I DO! I DO! in which four couples can play the roles. Now we'd get a chance to see Jones himself along with Nancy Ford play the fifth couple.

Daniel J. Edwards portrayed Michael when he, to cite a Jones lyric from his most famous show, "was a tender and callow fellow." He and Samantha Bruce went from that first night in their new house all the way to becoming the parents of a boy and a girl.

Bruce showed weariness when pregnant for a second time. Once the two gave way to Peter Saide and Janet Metz -- Michael and Agnes 15 years later -- "pregnant" had a different meaning. It aptly described the pause that Michael gave after Agnes implied that he was having an affair.

"Men of 40 go to town; women go to pot," Michael bragged in "It's a Well-Known Fact." The lyric could make an audience moan or hiss, but director David Glenn Armstrong and Saide found a solution. They had Michael come across as ridiculously cocksure from the moment he'd started singing. We immediately laughed at this stuffed shirt, so when he reached the lyric, we had a feeling of "Well, what else would you expect from this buffoon?"

We forgave him, too, when he realized that the angel you know is better than the devil you don't - and stayed married.

A twist came when Agnes was replaced by Andrew (Brad Oscar; Gerry McIntyre played Michael). Did switching sexes occur to Jones because of a lyric in "Where Are the Snows?" Back in the 20's when this scene occurs, "We used to be quite bright and gay" had a different meaning.

Both men were looking forward to "When the Kids Get Married" for then they'd have the time to play musical instruments. Martin actually fiddled a violin and Preston learned to play the saxophone, but Oscar and McIntyre showed that miming and making the sounds of the instruments were good enough.

When Lynn Wintersteller and Lewis Cleale took their place, Agnes emerged as an early feminist. She gave serious thought to ending the marriage because of "what I need" and "all these feelings I kept inside me that nobody knew." She stated that if she did indeed leave, "for you, it'll be Chapter Two; for me, Chapter One."

Eventually they compromised and even did a little fox-trot. This small moment reiterated that I DO! I DO! is easier to mount than most musicals because it demands little Dance. (Choreography was the one of the few categories at the 1966-67 Tonys for which it was eligible and yet wasn't nominated.)

Although the musical takes place in the long-ago, it showed that many aspects of an early 20^th century marriage are still relevant: the joy of the birth of children is followed by the difficulty in raising them. The fights lead to compromises and reconciliations. The happy anticipation that the children will soon get married and leave is followed by the emptiness after they do. Then comes the downsizing from house to apartment (which Jones and Ford played most tenderly).

The show may actually do your audience some good. It reminds us that a spouse should not be taken for granted and that a marriage must always be kept fresh. I DO! I DO! certainly seemed just that at the York.

Read more Filichia Features .

You may e-mail Peter at pfilichia@aol.com. Check out his weekly column each Monday at www.broadwayselect.com and Tuesday at www.masterworksbroadway.com . He can be heard most weeks of the year on www.broadwayradio.com.