Flippant wit aside, however, what does that mean? The answer can be found in "Prelude to a Kiss," which opened last week at the Repertory Actors Workshop.

The "Sisters" line is spoken by an extremely enthusiastic bisexual. The "Prelude" exploration of the meaning of both love and spare parts involves an extremely reluctant bisexual.

Playwright Craig Lucas ("Prelude") is the equal of Wendy Wasserstein ("Sisters") when it comes to vivid characters, witty dialogue and romantic incident. But Lucas' ingenious fable explores themes that are well beyond the limits of Wasserstein's drawing-room comedy: the nature of love, the connection between body and soul, and even the collapsed chronology that comes with AIDS.

Though "Prelude to a Kiss" recently came and went as a glossy movie, the Repertory Actors production does not suffer by comparison. Director David Hsieh has been especially resourceful in finding authoritative, mature actors: Andrew Tripoli as a suburban dentist and golf enthusiast and E. Dee Torrey as an irascible retired stationer with a bad liver and worse lungs.

Young performers are also authoritative. T.J. Langley and Colleen Parker are charming as quirky young lovers. Langley plays the reluctant bisexual. Imagine his consternation when - in an ironic reversal of the frog-to-prince fairy tale - his enchanting bride turns into an old man with cirrhosis of the liver and lung cancer!

Parker has trouble expressing her character's sometimes tragic, or at least neurotic, view of life. She is much stronger with the countervailing elements, the youthful radiance.

The kiss to which Lucas provides an intriguing prelude is between the reluctant bisexual, and the youthful (female) radiance transformed into aged (male) frailty.

Though AIDS is never mentioned, its ravages come to mind. AIDS sometimes ages people at the rate of a year every month, or even every week. The victims' partners confront a conundrum: This is, or is not, the person I love, or at least loved. What now?

The Repertory Actors cast of 14 does a delightful job both with sunny comedy and passing clouds.

Though always a hopeful writer, Lucas explored the dilemmas of AIDS directly in his script for the film "Longtime Companion."

"Prelude's" tone is more overtly amusing, but a cautionary theme of safety and prudence emerges in the final scene. The principal characters concur: always floss.