The teenage hoodlums who maraud through Arthur Laurents’s startlingly sweet new revival of “West Side Story” seem like really nice kids. Youth has always been the engine of this epochal musical from 1957, created by one of the most talented teams in showbiz history: Mr. Laurents (book), Leonard Bernstein (score), Stephen Sondheim (lyrics) and Jerome Robbins (director and choreographer). But usually it’s the scary, adrenaline-stoked energy of youth that sets the tone and rhythms of the show. In this production, which lovingly replicates Mr. Robbins’s balletic choreography, what prevails is a tenderhearted awareness of the naked vulnerability of being young and trapped in an urban jungle.

Half a century ago middle-class adult theatergoers were shocked and appalled by the brutality of the ethnic gang warfare of “West Side Story.” This time audiences — the grown-ups, anyway — are more likely to respond with feelings of parental protectiveness.