On the upcoming holiday of Shavuot, we will read the Book of Ruth, reminding us once again of the significant difference between conversion then and today. Speedy conversion seems to have been the norm in the days of Ruth, the woman who would become the grandmother of the ultimate king of Israel — King David. Contrast that with the official state conversion process and the associated procedures for establishing Jewish lineage that we have in Israel today. In recent years, the high bar set by halacha, Jewish law, for gaining recognition as a Jew has been raised even higher by a disturbing trend of using genetic testing to establish candidates’ Jewishness — essentially, a “geneticization” of the Jewish people.

Currently, such tests are private initiatives, which the state’s rabbinical courts are prepared to accept as evidence of Jewishness. The willingness by an official body to adopt genetic testing as proof of Jewishness marks the first step in the creation of a genetically-based Judaism and the widespread use of genetic databases. Beyond the fact that the use of genetics to prove Jewishness is distasteful, it constitutes a dramatic deterioration in the way we define the Jewish people. This is a revolution that must be nipped in the bud.

In Israel and around the world, there are hundreds of thousands of people who see themselves as belonging to the Jewish people but who would have a hard time in gaining official recognition as Jews from the Israeli Chief Rabbinate. After thousands of years in which membership in the Jewish people was largely a matter of claiming such membership, along with some halakhic evidence, the last three decades have seen the Chief Rabbinate adopting increasingly harsh procedures to establish the Jewishness of those who have immigrated to Israel. Many of these immigrants have been forced to endure a bureaucratic nightmare, for lack of the detailed documentation required by the rabbinate — and, in certain cases, have had to undergo a full conversion process.

In recent years, with advances in genetic science and the fact that genetic testing has become affordable and widely accessible, genetic tests have become a tool for rabbis and rabbinical courts to establish petitioners’ Jewishness. The rabbis’ underlying premise is that it is possible to identify certain genetic markers in the genetic profiles of some Jews, and thus anyone whose cells hold these same genetic markers is undoubtedly Jewish. Currently, the existing genetic markers make it theoretically possible to establish the Jewishness of some Jews, and presumably, if sufficient resources are invested in this project for a sufficient length of time, genetic markers can be found for most of the world’s Jews. Accordingly, against the backdrop of rabbinical willingness to accept genetics as proof of Jewishness, a genetic laboratory has now been set up with this very purpose, and is encouraging Jews to be tested and to add themselves to the database.

The trend towards making membership of the Jewish people contingent on genetics, and changing the means by which one proves membership, from a system based on trust and on flexible halakhic rulings to a system based on genetic identification, runs the risk of changing the very character of the Jewish people. As the database of genetic markers of Jews expands, and the number of Jews registered in this database grows, we will be dangerously close to a situation in which there will be two Jewish peoples: the “genetic” Jewish people, and the people who see themselves as Jewish, but are unable to “prove” it. In other words, we will have first-class and second-class Jews.

Currently, these genetic tests are carried out privately, but there are clear signs that the Israeli Chief Rabbinate and the rabbinical courts — the officially sanctioned bodies responsible for this issue — are willing to adopt this concept. Thus, for example, in the course of procedures to establish the Jewishness of petitioners to the court, judges are willing to accept the test results, and sometimes even hint that such testing should be carried out. This trend echoes another initiative being driven by the Chief Rabbinate — to create a database containing as much information as possible, so that it can be used to prove the Jewishness of Jews around the world.

In today’s world of big data, it is easy to imagine what the impact would be of a single database containing the genetic footprints — and other information about their Jewishness — of Israeli citizens, as well as other individuals around the world. Instead of being a Jewish people, we would become a Jewish database. Instead of a living, breathing organism, whose boundaries are defined by a combination of tradition, a desire to belong, and the willingness of halakhic authorities to expand the borders of the Jewish people, we would become a digital repository, managed by rabbis and controlled by background checks and blood tests, and providing the exclusive channel for achieving recognition as a member of the chosen people.