Who Determines Lineage? Father, Mother, and the Secret of Jewish Heritage

In Judaism, lineage has tremendous significance, and many Torah laws address various aspects of lineage. One of the most basic rules of lineage is that within the Jewish people, a child’s tribal affiliation follows his father. For example, if a Cohen marries a Jewish woman, the children will be Cohanim. But in the reverse case, if a Jewish man marries the daughter of a Cohen, the children will be Israelites. This rule applies consistently in marriages between tribes and between families. Yet, though within the Jewish people lineage is determined by the father, in marriages between Jews and non-Jews, lineage follows the mother. Thus, if a non-Jewish man marries a Jewish woman, the children are Jewish, and if a Jewish man marries a non-Jewish woman, the children are non-Jews in every respect.

This difference highlights the point that a child’s national characteristic is determined by his mother, while his tribal role within the nation comes from his father. This nuance raises an important question: Torah law also delineates rules of lineage among non-Jews themselves. In marriages between different non-Jewish nations, the children are affiliated by their father. For example, if a Moabite man marries an Egyptian woman, the children will be Moabites, not Egyptians.

To explain the difference between regular marriages, where lineage follows the father, and marriages between Jews and non-Jews, where lineage follows the mother, it is necessary to first understand what lineage is all about.

The Mishnah in Kiddushin (Chapter 3, Mishnah 12) states: "Wherever there is valid betrothal and no transgression, the child follows the male." This means that lineage is affiliated by the father not on account of the technical fact of fatherhood, but rather because the father is halachically betrothed to the mother of the child.  Accordingly, it is necessary to explain this “betrothal” that creates paternal lineage.

The essence of kiddushin (betrothal) is not merely to permit the woman to her husband. Beyond making her permitted to her husband, she becomes forbidden to everyone else, and he becomes obligated in the ketubah (marriage contract) which specifies his obligations to support her, clothe her, and care for her. Essentially, the purpose of kiddushin is to create a family unit. Only after the family is formed are the children born within this family framework affiliated by their father. Without the family unit, the children’s father is not connected to his wife, and consequently, not to his children. In the absence of a marriage that maintains family life, there is no family, and what remains is the natural, animalistic state where offspring belong to the mother for the simple reason that she gave birth to them. It follows that a biological connection is not sufficient grounds to connect children with their father. Instead, he is only called their father when the children are born within the family framework that binds him and his wife, making him their father.

Accordingly, the only way for Jews who are obligated in mitzvot to establish a family is through a halachic kiddushin process. And since the father is the head of the family, the children are affiliated with him. So - what happens if a Jew marries a non-Jew? Since kiddushin do not apply here, and mixed marriages between Jews and non-Jews do not have halachic validity since Jews are on a different level than non-Jews – there is no family, and consequently the children belong to the mother, whether she is Jewish and her husband is a non-Jew, or she is a non-Jew and her husband is Jewish. On the other hand, non-Jews are allowed to marry one another and they can therefore establish a mixed family between, for example, an Egyptian and a Moabite, and the child can be affiliated with the father.

The laws of lineage demonstrate that Torah laws and practices contain hidden lofty ideas that give expression to the differences between Jews and non-Jews, Israelites, Levites, and Cohanim, as well as the essence of our role, as Jews, among other nations of the world.