Parental guidance is strongly suggested for any kiddies who might want to go to the Kennedy Center's new production of "Christopher Columbus," an operetta Jacques Offenbach would probably stuff in the reject bin if he saw it in the Terrace Theater where it opened last night.

It is a naughty little show with unhappy brides, happy brides-to be, virgins and erstwhile virgins, and, as it insists in one line, "Not a virgin for miles around." If you like a gag show with lines your high school English teacher would have flunked you for, in which Christopher Columbus discovers America, Coca-Cola, the Statue of Liberty, Xenon, Bendel's and Studio 54 all at once, this might just be your show

There's no point to going over the plot so I will: Columbus, the stud of Cordova, with three wives - one Swiss, one Italian and one French - is caught making out with Isabella, Queen of Spain. Caught by King Ferdinand at that. For which he is sent off to find a new route to the Indies, which Isabella insists is exactly what he was doing when the king came in.

Anyway. The whole thing was thrown together by Patric Schmid (ni relation to Patrick Smith, president of the Music Critics Association) and Donald White. They thought Americans would love the low and high camp salute to this country in the year of the Bicentennial.

The music is all from all Offenbach shows, most of them deservedly buried for a century. Half of it could be called junk, starting with the over-ture. The other half often strongly reminiscent of medium Gilbert and Sullivan, works very well for what is asked of it.

The new production is done with some dazzling brilliance and some barely tolerable sophomoric carryings-on. I am sworn not to give away the secret of Elain Bonazzi's first entrance. But if you want to see one of the magic moments in music theater today, go see her Isabella. She could give lessons to Tallulah Bankhead, Lucille Ball and Carol Burnett. If the whole show could operate on her level, it would be an all-time smash hit.

Nothing however, will keep me from praising her final entrance, as the very Statue of Liberty herself, clutching in her left arm an enlarged copy of "The Joy of Sex," which is another of Columbus's major discoveries.

Neil Rosenshein has all the equipment needed to make the title role his personal triump. His virile tenor knocks off high Cs at an alarming rate, the hair on his chest arouses Bonazzi to delighted frenzies, and you can easily see how and why he wins wives without trying, up to and including the Indian Princess Minnehaha.

The cast is full of expert singers with exciting voices: Karen Hunt as Beatriz, Myra Merritt, Dana Krueger and Erie Mills as the French, Italian and Swiss wives, are all first-class. They are closely seconded by Chrissellene Petropoulos, Martha Steiger, Gail Mitchell and Valerie Eichelberger as the first quartet to throw you a wicked curve.

Lois Bewley's staging goes well in the first act but flounders into hopeless routines in the second. Brian Salesky got his conducting in good shape after a slow beginning, but then the show itself creeps for a while.

With handsome costumes and an elegant set for act one, visual impressions rank high along with the vocal assets. A serious word of warning: no one should be singing all those high C's and D's six nights in a row, but that's the schedule. That way lies vocal disaster, kids.Don't do it. The orchestra vacillated between sounding very plush and terribly raw and scratchy.