To answer the question that's spun off on a DNA-tastic tangent:    It's a little of both. It's for the most part a religion, but in entering into that religion you accept Jewish culture and accept Abraham as your ancestor. Once you become a Jew, you cannot un-become a Jew. It's too complicated to just put down as a religion, but at the  most  it's an ethnicity for Ashkenazi and Sephardic Jews, just like Irish or Italian is. What binds us together is Judaism, the religion and culture, and anyone who is commited can become a Jew - how in G-d's name can it be considered a race if this is so?