So, I’m on FB and I see this post:

Despite the worried look on the Orthodox Jewish man in the photo accompanying the post, I don’t think it’s particularly surprising to find out that after Jews lived in Europe for many, many centuries, their genetic heritage includes significant European components. Even in Ancient Israel, Jews were never a racial group or a hermetically sealed ethnic group. Israel is at the geographical meeting place of three continents, and empires based in all three of those continents conquered and intermingled with the ancient Judeans over a long period of time. The reason I presume that Jews who’ve lived in very different parts of the world over time have come to physically resemble the people in the dominant cultures in which they’ve lived is that there has always been a certain degree of intermarriage and of conversion. Also, as this article points out – as far back as 2600 years ago, with the Babylonian exile of a large part of the Israelite population, there’s been a sizable Jewish diaspora throughout different parts of the Middle East. Greek and Roman domination of ancient Israel also facilitated movement of some Jews to the big cities and ports of the Mediterranean.

What worries me about these genetic studies is how quickly they tend to get used, in the form of ideologically motivated pseudo-science, to make absolutist “racial” claims about whether or not the Jews have a national connection to the land of Israel, or whether or not the Jews are “really Jews.” But who says that blood and genes are what defines the Jewish people?

I think it’s fair to say that ethnic/religious communities get to decide for themselves how they define themselves. In the case of the Jews, there have been several ways that people have become part of “the tribe.” For 1000 years or so, the children of Israelite fathers, not mothers, were considered Jews-by-birth. Roughly around the time of the Romans, the early rabbinic community facilitated a shift to defining Jewish identity by birth to the mothers. But people could always convert, and at different times during the very long sweep of Jewish history, significant numbers of people did.

And no, I’m not referring to the whole meme about the entire Kingdom of the Khazars converting en masse in the Middle Ages, which has become a trope in an anti-Semitic conspiracy theory that basically argues that Ashkenazi Jews aren’t “real Jews” because they almost all descend from the (utterly unproven) “Khazar conversion,” and therefore the Ashkenazi Jews of the world maintain a public lie about their very identity, and then – the conspiracy theory tends to go – use that lie in order to justify their support for the state of Israel.

The conversions into Judaism by meaningful numbers of people that I’m referring to took place in many different lands where Jews lived in Diaspora communities. In Rome, in what is now Turkey, in Persia, in Egypt, in Greece, etc. Jews aren’t and have never been a racial group. People have not needed to be born into the group to join the group, and the transmission of Jewish identity from generation to generation has been more about community, shared beliefs, shared ritual and cultural practices, and a shared sense of history and destiny than the “purity” of bloodlines. As Rabbi Jack Cohen, z’l, once wrote:

“Throughout the long age from the destruction of the 2nd Temple in 70 C.E. [until the modern era, the Jews were] a unique, spiritually motivated and united trans-territorial society.”

So the genetic stuff is interesting, but it doesn’t tell us all that much, nor does it qualify or disqualify real people from their understandings of their own identities.