This incredibly powerful graphic is a bit misleading when considering matra-lineal lineage. For example, if you have 50 Jewish men and 50 Jewish women in a population and each one marries outside of Judaism with an even Steven 50% interfaith marriage rate and a birth rate of 2 children per mother, how many Jewish children will they produce in the first generation? Second? Third? It is a trick question.
Assuming the thousand(s) year old definition of a Jew as being born from a Jewish mother or converting to Judaism, the answer to the above question is that there would be the same number of Jews in three generations. The 25 Jewish men that married gentiles would be replaced by the two children of the 25 women who married gentiles. The implications of this are frightening when we consider American Jewry. This would translate to millions of American Jews today who no longer identify as Jewish.
Accordingly, the chart below really represents those who identify as Jewish. This calculation predicted the famous Pew Study decades ago and according to many, is a proof that Orthodox is the only movement that successfully prevents interfaith marriage.
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