For the most part, Romeo and Juliet are star-crossed lovers simply because we are told in the introduction that they are. Shakespeare lays out the entire situation for us in the beginning and even tells us that the outcome will be tragic. We can see evidence that they are star-crossed throughout the play. First, their families hate each other. They have parents who do not support their union. They have to run away to get married, and when they manage to do so, they end up dying tragic deaths. In the end, the only way for them to be together is through death- there is no happy ending for them. Thus, they are star-crossed and there would not have been anything either of them could have done to change the situation because this was laid out for them from the beginning.