Cousin Marriages

Does the Torah permit cousin marriages? Is the topic discussed at all? I’m concerned in particular because the inbreeding is likely to cause genetic disorders, as historically happened to many royal families. I have the impression that upper class Jewish families have likewise engaged in this practice.

The Aish Rabbi Replies:

It is permitted under Torah law for cousins to marry. In fact, the Sages seem to view marriages between relatives as desirable. The Talmud recommends that a person marry his niece (Yevamot 62b). (There’s a debate in the commentators if it applies specifically to a sister’s daughter or also to a brother’s.) The assumption is that a person will have an especially close relationship with a close relative, perhaps because of their likely similar personalities and values. The reasoning may be the same for a cousin, but the Talmud doesn't mention it. (I should point out that for a woman to marry her nephew is forbidden from the Torah – Leviticus 18:12-13.)

Some point out that the daughters of Zelophehad married their cousins (Numbers 36:11) so the practice has good precedent. Some also suggest that cousin marriages are likely to engender fewer fights between the in-laws!

In terms of the genetic issues, you are right that relatives who marry should be even more careful to do genetic screening in advance. The Talmud is referring to a single instance rather than a long-term practice. Of course, since Ashkenazi Jewry descends from a very small group of ancestors many of us are already stuck with significant genetic issues.

I should add that Jewish law obligates us to abide by the law of the land. Since many US states and locations worldwide forbid cousin marriages, one may not marry his cousin in such locations according to Jewish law as well.

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