According to the Jewish/Christian creation (Genesis) and the Jewish law, everyone is a Jew.
1) God created Adam and Eve. What religion were they? The only religion there was, Jewish.
2) They had children. Weather or not they practiced Judiasm, according to Jewish law, seeing as how they had a Jewish mother (Eve), they were Jews.
3) Adam and Eve's grandchildren had Jewish mothers (see #2).
4) Repeats itself over and over, until we get to Noah and his wife, who were Jews.
5) Again, this repeats itself until we get to right now, where we are all decendants of Noah and his wife, and in turn Adam and Eve. We are all Jewish.
G_G.