Matrilineality in Judaism or matrilineal descent in Judaism is the tracing of Jewish descent through the maternal line.
Historical evidence marshalled by Professor Shaye J. D. Cohen indicates that a change from a patrilineal to a matrilineal-based principle for the offspring of mixed unions of Jew and gentile took place in the 1st century (c. 10–70 CE) times to Modern times.
Different theories try to explain the shift to matrilineality in Judaism. Some Hasidic Jewish groups propose that matrilineality and matriarchy within Judaism are related to the metaphysical concept of the Jewish soul. Conservative Jewish theologian Rabbi Louis Jacobs suggests that the marriage practices of the Jewish community were re-stated as a law of matrilineal descent in the early Tannaitic Period (c. 10–70 CE).
Contemporary practice of Jews
The practice of matrilineal descent differs by denomination. Each denomination has protocols for conversion for those who are not Jewish by birth.
Conservative Judaism
The Conservative Movement practices matrilineal descent. In 1986, the Conservative Movement's Rabbinical Assembly reiterated the commitment of the Conservative Movement to the practice of matrilineal descent. Furthermore, the movement stated that any rabbi who accepts the principle of patrilineal descent will be subject to expulsion from the Rabbinical Assembly. Still, the Conservative Movement affirmed that "sincere Jews by choice" should be warmly welcomed into the community and that "sensitivity should be shown to Jews who have intermarried and their families." The Conservative movement actively reaches out to intermarried families by offering them opportunities for Jewish growth and enrichment.
The Ratner Center for the Study of Conservative Judaism conducted a survey of 1,617 members of 27 Conservative congregations in the U.S. and Canada in 1995. 69% of respondents to the Ratner Center survey agreed that they would regard personally as a Jew anyone who was raised Jewish—even if their mother was Gentile and their father was Jewish (Wertheimer, 59). In this same survey, 29% of respondents indicated that they attended Jewish religious services twice a month or more and 13% that they engage in the study of a Jewish text once a month or more (Wertheimer, 55–57).
Karaite Judaism
Karaite Judaism does not accept Jewish Oral Law as definitive, believing that all divine commandments were recorded with their plain meaning in the written Torah. As such, they interpret the Hebrew Bible to indicate that Jewishness can only follow patrilineal descent.
The majority view in Karaite Judaism is that Jewish identity can only be transmitted by patrilineal descent. They argue that only patrilineal descent can transmit Jewish identity on the grounds that all descent in the Torah went according to the male line. Only someone who is patrilineally Jewish (someone whose father's father was Jewish) is regarded as a Jew by the Mo'eṣet HaḤakhamim, or the Karaite Council of Sages based in Israel.
Both Rabbinic and Karaite Jews lived in 12th century Egypt, and a number of marriage contracts between Karaite and Rabbinic individuals have been discovered in the Cairo Genizah. The Egyptian Karaites followed patrilineal descent, but forbade marriage with non-Jews and also did not allow converts into their community. In effect then, 12th century Egyptian Karaites required that both parents be Jewish, but they referred to this requirement as patrilineal descent. Thus, marriages between Karaites and the Rabbinic community did not violate the Rabbinate requirement of matrilineality. However, these marriages came to a halt when Maimonides (who led the Rabbinate Jewish community in Egypt in the late 12th century) prohibited them for a separate reason: while he considered Karaites Jewish, he also considered them to potentially fall within the category of mamzerut, as their divorces were not conducted according to Rabbinate standards.
Orthodox Judaism
Orthodox Judaism practices matrilineal descent. Orthodox Judaism holds that anyone with a Jewish mother also has irrevocable Jewish status; that even were such a Jew to convert to another religion, that person would still be considered Jewish by Jewish Law.
Reconstructionist Judaism
Reconstructionist Judaism was the first movement to adopt the idea of bilineal descent in 1968. According to Reconstructionist Judaism, children of one Jewish parent, regardless of gender, are considered Jewish if raised as Jews.