I attend a Bat Mitzvah program at our Temple where most of the kids have one Jewish parent. A bit of an argument broke out over who is the better Jew – someone who has a Jewish father, or someone who has a Jewish mother. The rabbi didn’t know the answer. Who is right? Thank you, Rachel Cohen.
The Aish Rabbi Replies:
Jewishness is passed on via the mother. If the mother is Jewish, the child is 100% Jewish. If only the father is Jewish (but not the mother), then the child is 100% not Jewish. Jewish identity passed on through the mother has been universally accepted by Jews for 3,300 years, and was decided by God, as recorded in Deuteronomy 7:3-4. The Talmud (Kiddushin 68b) explains how this law is evident from those passages. Modern attempts to revise this law have caused a dangerous split in the Jewish people.
In another sense, however, the father does passes on lineage, in terms of which tribe the child belongs to. This determines whether the child is a Cohen, Levite, or Yisrael. See Numbers 1:20-46 which explicitly categorizes the Jewish people by their "father's house."
Of course, in the event that one’s mother is not Jewish, there is no significance to which tribe the father comes from, since the child is anyway not Jewish.
It should be noted that just because someone's last name is "Cohen" doesn't mean that he has the status of a Kohen. To be considered a Kohen, one must have an unbroken tradition, as well as other factors too numerous to mention here. Nevertheless, it does turn out that many people who have the name Cohen also have the status as Kohen.
From the fact that the religion of the child goes by the mother, while the tribal affiliation goes by the father, we see that both parents must take an active role with the child. The mother is entrusted with the awesome duty of instilling in the child faith in God, observance of mitzvot, and Jewish pride. By way of metaphor, we see that the mother gives the baby food and love that brings out its internal potential. This is in contrast to the external qualities, represented by tribal affiliation that is the father's duty.
Feel free to write back if you have any more questions.