And even if you convert to Judaism,they have a whole set of categories ranging from the Kohen(priest)downwards;converts(known as gherim)are the lowest!There is a talmudic doctrine that says that if you have to chose to save the life of a Jew among several ones who are in danger,you have to save first a Kohen,the a Levi,then an Israel(the common average jew without 'titles'),than a mamzer(a bastard)and finally a convert.Besides this,converts all bear the patronimic 'ben Avraham our father'and the matronimic 'ben Sarah our mother',so every born Jew immediately knows they are second rate Jews and can discriminate against them.