"Man, Woman and Child," adapted from Erich Segal's book, secretes artificial sweetness and lite -- all the cloying, sticky stuff we've come to expect from the pen of America's sob-sister emeritus. The screenwriters have churned Segal's modish, meaningless platitudes into verbose goo, while the conductor has added a sappy score with notes like overripe plums attracting fruit flies.

Martin Sheen, a 78 at 45 rpm, plays droopy professor Bob Beckwith, whose incredible fertility gives birth to the scenario, which simultaneously achieves predictability and implausibility. Suddenly, Beckwith learns that he is the father of a 10-year-old boy, the result of a two-day affair with a French country doctor who has just died in an accident.

There's a Hallmark-card flashback of a seaside conception -- silhouettes running, as best they can, in waist-high salt water, then meshed against an orange sun. Coupled with the visuals are such groaners as Bob's precoital come-ons, a kind of literati bar- speak: "What do you like most about Baudelaire's work?"

This intercourse produced a mopey moppet named Jean-Claude (Sebastian Dungan) who comes to visit Bob, his fuming wife Sheila (Blythe Danner) and his unknowing half-sisters Paula (Missy Frances) and Jessica (Arlene McIntyre).

The distaff trio, plus Sheila's best pal Margo (Maureen Anderman), are at least animated. But the minute they start smoking, the writers spoon-feed treacle. For example, when Margo is cheering up Sheila, she gets off a couple of quips -- "One affair in 10 years is practically celibacy." And "I was a virgin for practically a year before my divorce." But this perk-me-up ends in the sort of Segalism we've come to expect: "I envy you," says Margo, who just wishes she could love any man as much as Sheila does.

The tension, stringy as cheese on a pizza, centers on Sheila's attitude toward Bob. Will she accept his bastard, conceived while she was pregnant with their youngest child? It's sort of like asking a dog to mother a wolf. Sheila, an editor for the university press, resents it enough to have a glass of brandy with another man -- David Hemmings, who has blown up since "Blow Up." Luckily she isn't that desperate, even if the film is.- MAN, WOMAN AND CHILD -- At area theaters.