According to Jewish law, a Jew is one who is born to a Jewish mother or is converted to Judaism. Therefore, a child who is born to a Jewish father and a non-Jewish mother is not Jewish even if raised with a Jewish identity. Prior to the 1960s, when intermarriage in the United States was relatively uncommon, this law had few practical consequences. Today, however, more than one third of Jews intermarry and, more often than not, it is Jewish men who marry non-Jewish women. As a result, there are an estimated 220,000 children in the United States born to nonJewish women who are married to Jewish men.
In 1983, the Reform movement broke with Orthodox and Conservative Judaism, and with Jewish law, and declared that a child born of one Jewish parent, whether it is the mother or the father, is under the presumption of being Jewish, but that his/her Jewishness must be activated by "appropriate and timely" Jewish acts. It is not enough to simply be born to a Jewish parent. The Reform movement also notes that in the Bible the line always followed the father, including the cases of Joseph and Moses, who married into non-Israelite priestly families.
The Reform decision to regard a child as Jewish on the basis of patrilineal as well as matrilineal descent has prompted a bitter controversy. In the future, traditional Jews who wish to marry a Reform Jew will have to examine their prospective spouse's background to ensure that he or she is Jewish according to Jewish law. In truth, however, the Reform movement's change is not nearly as great as it first seemed. Had the Reform rabbis maintained the traditional definition of a Jew, and insisted on converting children of non-Jewish women married to Jewish men, Orthodox Jews would still have considered the conversions invalid, since they reject the validity of Reform. (It should also be noted, however, that in the case of a child born to a Jewish father but to a non-Jewish mother, most Orthodox rabbis will relax the stringent demands normally made of would-be converts.)
Within the Reform movement, a significant number of rabbis opposed the ruling, and a few have agitated to have the decision rescinded. That might occur only if the Orthodox rabbinate agrees to accept the validity of Reform conversions. Since no such agreement seems to be forthcoming, the Reform decision apparently passed in large measure to accommodate and reassure the tens of thousands of intermarried couples who belong to Reform synagogues will undoubtedly remain in force.
Within the Conservative movement, a minority attempt to define Jewishness on the basis of paternity as well as maternity has been soundly defeated.
Source: Joseph Telushkin. Jewish Literacy. NY: William Morrow and Co., 1991. Reprinted by permission of the author. Also Union of Americah Hebrew Congregations.