Peer pressure: this is seen when the gangs are about to have a rumble and some of the members don’t want to use weapons or even fight. By looking at this scene closely you see that they seem to be forced to do so to stay in that gang. As well as Maria being forced to accept Chino’s marriage proposal which is also in Romeo and Juliet where Juliet is being forced to marry.
Family: There is a bond between Maria and Bernardo that is seen, where Bernardo is seen as being overprotective. It looks like he needs to protect Maria due to something happening in past possibly. This is a great example of a strong bond between family members but he seems to almost push her away with all the smothering behaviour he surrounds