"It's My Turn" promises to inspire a higher percentage of blank stares, stifled yawns and "so whats" than any other recent fiasco. At the coyly inconclusive fadeout, which finds Jill Clayburgh once more lost in wistful reflection about the prospect of a new romance, I clutched rather desperately at the title song, crooned by Diana Ross, hoping that the lyrics would impart some meaning to the trival sequence of events that had just petered out.

Perversely, the tune reinforced the banality of the movie: "If I don't have all the answers/At least I'll take my share of chances." One gathers that whatever it is, the heroine will do it her way. But what does it matter when she seems the droopiest of protagonists and love objects?

Perhaps Clayburgh should play a sandhog or gangster in her next movie. She's becoming a crashing melancholy bore in the ongoing symbolic role of Ms. Will-She-or Won't-She, unable to decide whether she should trust nature and grab for the gusto when attractive suitors appear within her tentative grasp.

The excruciating irony built into "My turn," a platitudinous update of the old-fashioned Woman's Picture, is that the heroine is supposed to be a brainy sort who knows all the answers. Kate Gunziger, you see, teaches higher mathematics at a university in Chicago. She's introduced in the classroom, analyzing some intimidating equation and trying to brush off a persistent, precocious student (Daniel Stern, who played the self-mocking, witty Cyril in "Breaking Away").

Kate shares a downtown loft with a divorced contractor, Homer, played by Charles Grodin. The relationship is defined by chafing, brittle repartee that betrays a vulnerable domesticity. This superficial romance obviously waits to be swept aside.

Kate goes to New York to investigate a job offer and attend the marriage ceremony of her widowed father (Steven Hill). At first inclined to resent her new stepmother (Beverly Garland), Kate relents and begins to envy her contentment. She also discovers that passionate attachment in the form of her new stepbrother, played by Michael Douglas.

A former professional baseball player forced into premature retirement by an injury, Ben introduces Kate to a whole new colorful side of life. She finds herself cheering like any old fan while watching Ben at an Old Timers' Game at Yankee Stadium, an interlude that accommodates walk-ons by Bob Feller, Mickey Mantle, Roger Maris and many other diamond luminaries.

The Hollywood filmmakers of a generation ago would have gratified their audience by resolving the affair of new lovers like Kate and Ben. It's a maddening new affectation on the part of writer Eleanor Bergstein and director Claudia Weill to leave the affair dangling -- but you don't begin to give a damn anyway. The idea that Kate is an interesting and desirable woman never takes hold. Neither does the idea that Ben represents a significant improvement on Homer. The triangle in "It's My Turn" adds up to a strike-out.

I wasn't impressed by Weill's lowbudget feature "Girlfriends," but it was easier to respect than this film. Weill seems sincerely drawn to intimate subject matter and nuances of middle-class behavior, but her interest is wasted on writing ad counterfeit as Bergstein's. The situations may seem intimate, but the characters can't escape their synthetic soulful talk and cliched functions.

Weill doesn't help by imposing additional layers of romantic cliche. The sex scenes go into a lyrical swoon, and Patrick Williams' neo-baroque score serves as a constant reminder that we're dealing with the love life of a cultivated, classy woman and no mere academic tootsie, so be suitably impressed.

What is it Kate really wants? She tells Homer, "I just want to be more connected, to feel we nurture each other." Not a very eloquent or nourishing morsel of psychobabble, I'm afraid. Homer evidently loses out by declining to take this sentiment to heart, but one suspects that it was an astute act of avoidance.