From the very beginning, Romeo and Juliet are "star-cross'd" as children of "fatal loins." But Shakespeare knows that the events leading to tragedy cannot be explained away so simply.
In the prologue to Act 1, an actor playing the chorus recites a sonnet in which he describes the bitter hatred dividing the Montagues and Capulets and identifies Romeo and Juliet as lovers who had the misfortune to be born into warring families: “From forth the fatal loins of these two foes [the Montagues and the Capulets] / A pair of star-cross’d lovers take their life” (lines 5-6).
Romeo and Juliet 'Star-crossed lovers' or tragic protagonists
The reader knows immediately that Romeo and Juliet are going to die after reading the prologue so the questions are asked why would two star-crossed lovers end up dying....