A Case for Genetic Jewishness
In the book Legacy, geneticist Harry Ostrer argues that Jewishness is biological, not just cultural
Ostrer’s careful and understated analysis of the evidence makes his arguments convincing. He is nuanced and doesn’t pretend that science has all of the answers about how Jews should feel about their identity. “The stakes in genetical analysis are high,” he writes, noting that they touch “on the heart of Zionist claims for a Jewish homeland in Israel.” Admixture with non-Semitic groups, in fact, “may absolve Jews from Christ-killing,” he writes. And he rejects the idea that his and others’ work would have pleased Hitler: “We were not seeking to develop a hierarchy of human groups nor attempting to eliminate individuals on the basis of their having ‘undesirable’ genes or traits, as the Nazis had.”
So, if Jews have common genetic markers, can a gene test (like the ones already being marketed) really tell you if you’re Jewish? “[T]here is no rigorous genetic test for Jewishness, nor would the geneticists who have conducted studies in recent generations propose that one should be created,” Ostrer writes. “Moreover, such a test would not replace the religious definition of who is a Jew.” The Israeli Law of Return, for example, doesn’t have a genetic requirement.
And even if such a test existed, it would need constant updating. Because even though Jews have maintained certain common genetic traits for millennia, those traits are likely to change at a rapid pace in the coming years. Jews are intermarrying at increasing rates. One of the genetic studies Ostrer quotes found that about 30 to 50 percent of couples that include Jews are now interfaith, compared to one in 200 couples per generation, on average, over much of human history. And people with a predilection for diseases that might have killed them before they passed on their genes are living longer, thus keeping certain traits in the Jewish gene pool at higher rates than would be expected from natural selection over time. Today’s Jews “are making spousal choices and using genetic information for disease treatment, disease prevention, and embryo selection to determine who future Jews will be,” Ostrer writes.
Jewish genetics, in other words, will change over time just as Judaism’s spirituality, social values, and culture have changed over the centuries. All of those characteristics help answer the question of what makes someone Jewish, but what made someone Jewish a thousand or even a hundred years ago is likely not how someone asking that question in a hundred years will answer it. Ostrer quotes Albert Einstein, who said in 1955 that his “relationship to the Jewish people has become my strongest human tie.” He also wrote: “In the philosophical sense there is, in my opinion, no specific Jewish outlook.”
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