 Due to the nature of their relationship and the difference between an alien boy and a human girl Max and Liz relationship is considered another modern example of forbidden lovers with many references to Romeo and Juliet through the series by both the characters and the writers/producers.Most notable examples are when Maria De Luca called them ""modern" Romeo and Juliet against the world"  or when Liz Parker herself used the tragedy of Romeo and Juliet into one her own tragic speech in the episode ""The end of the world"" from season two.The producers and writers of the series weren't unaware of the parallelism.