Jewishness: Who is a Jew? | The Economist: For Orthodox Jews like Rabbi Tubul, the solution is simple and ancient: you are a Jew if your mother is Jewish, or if your conversion to Judaism accorded with the Halacha, Jewish religious law. Gentiles might be surprised that for Jews by birth this traditional test makes no reference to faith or behaviour. Jews may be atheist (many are: apostasy is a venerable Jewish tradition) and still Jews. Joel Roth, a Conservative rabbi at the Jewish Theological Seminary in New York, likens this nativist criterion to that for American citizenship: Americans retain it regardless of their views on democracy or the constitution. Some strict rabbis even think that a child is not Jewish if born to a devout mother but from a donated gentile egg.
As some Jewish leaders privately acknowledge, this formula has uncomfortable racial undertones.