Who is to blame for the death of Romeo and Juliet in Shakespeare's play Romeo and Juliet?

On one hand, one might claim that Romeo's and Juliet's parents are to blame for their children's deaths.  After all, these children were raised in a culture of aggression where they have learned that hating their family's enemy is crucial and that violence is often the answer to problems.  Were it not for the families' grudge against one another, Romeo and Juliet might have been free to tell their parents about their feelings or they might not have been so quick to jump to violent action as an answer.

On the other hand, one could blame the Nurse and Friar for the deaths of Romeo and Juliet.  Romeo and Juliet are children, and they are encouraged by these two adults who they trust to go forward with the relationship.  The Nurse serves as a go-between for them, the Friar marries them in secret, and he even comes up with the plan for Juliet to fake her own death.  If the Nurse and the Friar had advised the couple to speak with their parents, it is possible that they would not have ended up dead.  It is even possible that their parents might have been supportive of the match.  The chorus says in the prologue that Romeo and Juliet come from "two households, both alike in dignity," and this statement makes it clear that the families are equal in status.  Further, when Tybalt gets angry that Romeo has attended the Capulets' party uninvited, Lord Capulet says that "Verona brags of [Romeo] / [As] a virtuous and well-governed youth" (1.5.76-77).  In other words, then, he has nothing against Romeo, personally, and has actually heard good things about him.  Further, at the end of the play, when the deaths of these youths have been discovered, Montague vows to erect a golden statue of Juliet to honor her faithfulness, and Capulet makes a similar promise to commission a statue of Romeo to lie by "his lady's" (5.3.314).  Thus, when the families learn how much their children loved each other, they try to honor that love.  Therefore, it seems entirely possible that if the Nurse and Friar had encouraged the lovers to be honest with their families, the play might have turned out very differently.