What if you turned a street corner and stood face to face with a genetic copy of yourself? Would you die from shock? Run away in fear? Or want to sue the scientists who harvested your cell line and stole a part of your uniqueness?

That conundrum arises from one of the many fascinating conversational tangents in A Number, Caryl Churchill’s 2002 play about the ethics of cloning, now receiving an engrossing revival at People’s Light.

In the play, Bernard (Nathan Darrow) visits his father (John Dossett) after a doctor informs him he is merely one of “a number” of genetically identical clones, of which he may or may not be the original). The father first feigns surprise, then slowly — between visits with another version of Bernard (also Darrow) — strips away layers of the past that led to a present in which more than one copy of Bernard’s genes exist in fully mature human form.

Over its 60-minute run time, Churchill’s play explores the impact from multiple perspectives. Father and (each multiple) son indulge in grief and recrimination. Through long silences, with his mouth hanging open, Bernard 2 wrestles with his diminished identity; Bernard 1, by contrast, fumes murderously over Salter’s need to correct parental wrongs.

During each scene, Eliza Baldi’s direction isolates the pair in a cell-like room, bare but for carpet, a small table, and a leather recliner. Thin rays of light (in Amith Chandrashaker’s lighting design) flow through a small, ceiling-height window in Andrew Moerdyk’s set. Very little action happens on stage as each father-son coupling struggles with the consequences of cloning.

Yet Darrow and Dossett punctuate each scene with moments of crippling intensity. Churchill’s scattershot dialogue thumps like a pounding headache, and the pair’s delivery forces us to acknowledge the weight of sorrow and loss in each measured, breathy line. Darrow’s skillful performance weaves subtle mannerisms and habits of speech into each of his copies, individualizing each clone’s character where appearance cannot.

Churchill wrote A Number after the Dolly the Sheep cloning bombshell. Since then, scientists have continued to push forward the boundaries of genetics. People’s Light’s production teases out the human implications, proving that her play still bristles with complications no technology or scientist can eliminate.

THEATER REVIEW

A Number

Through June 9 at People’s Light, 39 Conestoga Rd. Malvern. Tickets: start at $43. Information: 610-644-3500 or peopleslight.org