In Romeo and Juliet, is Fate or the rivalry between the two families the main reason for Romeo's and Juliet's deaths?

One could probably weave both elements together.  Perhaps,
it was fated that the two lovers would come from families that hate one another.  This
could be an approach to take both elements into one thought provoking perspective.  Yet,
if a choice was forced, I think that the rivalry between the two families is the reason
for their deaths.  It can become an intensely regressive discussion if we argued this to
be fated, but in my mind, Romeo and Juliet are forced to go to ends that bring about
their own deaths because of their families' intense hatred for one another.  If the
families do not hold disdain for one another, the two do not have to go to such
extremes, concoct plans where deaths are "faked," and take the risks that they do.  One
need only see Juliet and the interaction with her parents in Act III, sc. 5 to see the
level of intensity that the parents forced upon their children.  In the end, the kids
had no chance for their love, or their belief in love, to develop.  They had to pursue
channels outside of their parents, which means that the parents, and not fate were the
main reason for their deaths.