There are two theories that apply to the analysis of Romeo and Juliet's fate and whether it was a predetermined outcome of tragedy.
"Thus the theme of fate versus free will emerges: do Romeo and Juliet die because it was their destiny, or do they die because of their actions and the actions of those around them?"
Fate seems to predestine Romeo and Juliet due to the ungoverned hatred that exists between the two families, the Montagues and the Capulets, and the fact that they can fight openly, hate openly and not be stopped, it appears that Shakespeare has doomed his tragic young lovers from the start. And, in fact, used them as a sacrifice in order to put an end to the hatred between the two families.
But, within the play's action, there appears to be room to consider that Romeo and Juliet's hasty behavior, or free will, fueled by teenage passion contributed more to their deaths than their families dispute.
Romeo and Juliet are very quick to arrange their future together, but they lack a basic component that would insure its success, good communication. Caught up in a whirl of romance and urgency, the two young people take dramatic and permanent measures before they have all the facts or can communicate with each other.
In my opinion, I feel that, if this were not intended to be a tragedy, Romeo and Juliet could have found a way to urge their parents to come to terms with their union.