Unlike Buddhism, Christianity and Islam, Judaism does not have a missionary impulse. That is why there are so few Jews in the world. Mormons, who very actively seek converts, already outnumber Jews even though Mormons have been around less than 200 years; compared to more than 3,500 years for Jews.
Of course, the Mormons have worked hard to increase their numbers. The Deseret News, a Mormon newspaper reported in August 2013, that more than 85,000 missionaries are expected to be working all over the world by the end of the year.
Jews on the other hand have only at the most, a few hundred Jewish outreach personal; who mostly confine their efforts to seeking out only non-Jews with Jewish ancestry.
Almost all Jews are proud of Judaism’s lack of missionary zeal and activities, but very few Jews are aware of the heavy price Jews have payed genetically for going even further; and actively discouraging non-Jews from becoming Jewish.
Ashkenazi Jews have an unusually high risk of several genetic diseases, and up until now, no one understood why. Disease mutations unusually common in Ashkenazi Jews are: Tay-Sachs disease, some forms of breast cancer, high cholesterol, hemophilia and several less known diseases. Four of these disorders, including Tay-Sachs disease, are in a class of diseases called lysosomal storage diseases. People with these disorders lack enzymes that break down toxins into harmless compounds.
“It’s been known for a long time that Ashkenazi Jews have a high risk of these lysosomal storage diseases,” said Neil Risch, PhD, professor of genetics, statistics, and health research and policy at the Stanford University School of Medicine. “The majority opinion has been that there must be some selective advantage for those mutations.”
Risch and his colleagues analyzed DNA sequences from Ashkenazi Jewish people and compared how common mutations were in lysosomal storage disease genes vs. other disease genes. The researchers found that mutations in lysosomal storage disease genes are no more common than mutations that cause other inherited diseases in the Ashkenazi Jewish population.
This suggests that carriers for lysosomal storage mutations had no benefit over their non-Jewish peers. Then why did the percentage of Jews with these genetic defects increase, rather than decrease compared to their surrounding non-Jewish populations?
These mutations were probably present in the Ashkenazi Jewish population more than 800-900 years ago, and Jewish parents passed them along to their children, because Ashkenazi Jews in the 12th to 18th century all married within their own small population.
But it is also true that European Jews were prohibited by the Church from accepting converts to Judaism who would have reduced the chances of inheriting genetic defects. Both factors contributed to keeping those mutations common. The final mutations cropped up in Lithuanian Ashkenazi Jews about 12 generations ago.
All of these mutations would have been reduced by the entry of non-Jews into the Jewish gene pool through conversion to Judaism. Because conversion was severely restricted by the European Church from the 4-6th century on, converts to Judaism were not able to help eliminate these harmful genetic mutations.
If there is a substantial rise of conversion to Judaism in the 21th century, these harmful mutations will substantially decline by the end of this century.
But, will there be a significant rise in the number of converts? Judaism lacks a strong missionary impulse because Judaism is a pluralistic religion.
Judaism teaches that the Jewish way is right for us, but good people in other religions also have a place in the world to come. Correct behavior in society is more important than correct beliefs about God.
Thus, while Jews should welcome non-Jews to join us, many Jews, including some rabbis, see no reason to encourage conversion; and so do not welcome interested non-Jews who desire to become Jewish.
Lacking the missionary impulse of more universalistic religions, Jews react to potential converts in varied ways, ranging from wariness to encouragement. Practical community concerns guided many of out Sages. Some like Rabbi Helbo said that converts are an irritation like an itch, a sore or a scab.
Perhaps Rabbi Helbo felt that the enthusiasm and idealistic expectations of converts irritated too many born Jews, who take their Jewishness much more casually. Or maybe he agreed with Rabbi Isaac who said “Evil after evil comes upon those who receive converts”.
Both these Rabbis lived in the early 4th century when the Church was vociferously attacking pagans who choose to become Jews rather than Christians. Perhaps they feared Christian anti-Semitism if Jews were openly receiving converts.
On the other hand, Rabbi Simon ben Lakish proclaimed that a convert is more beloved to God than all the Jews who stood at Sinai. Perhaps he was reacting to those who claimed Jewishness was in their noble genes. Or perhaps he very much admired anyone with the courage to join a minority people.
Equally amazing were Rabbi Eleazar ben Pedat and Rabbi Yohanan who both taught that the forced exile of the Jewish people among the Gentile nations was really a God given opportunity to influence many Gentiles to become Jewish.
Some Rabbis tried to test the sincerity of potential converts by making great demands of time and effort from them. Opposing this Rabbi Yohanan advises that you should push potential converts away with your left hand and draw them close with your right hand. Since most people are right handed if you actually push away more than a few non-Jews you are being too negative.
Rashi, the greatest of our Bible commentators, taught that Jews started seeking converts from the very beginning, when he interpreted a verse that states that Abraham made souls in Haran, to mean that Abraham and Sarah made converts.
And the Talmud (Sanhedrin 99b) condemns those who push potential converts away by relating that Isaac and Jacob pushed away Timna the sister of Lotan who wanted to become Jewish. She then married a son of Esau. One of her descendants was Amalek who attacked Israel shortly after they escaped from Egypt.
If, instead of being pushed away, Timna had become Jewish, Amalek would have been on our side, and not one of our enemies. A more practical view is hard to imagine. It should guide all rabbis today in the State of Israel who deal with potential converts.
Indeed, Rabbi Yohanan says the Jews were oppressed and enslaved in Egypt because Abraham didn’t try to influence some captives that he rescued to become Jewish. Even failing to encourage potential converts is wrong according to Rabbi Yohanan.
The Talmud says Jews suffered the great damage of being enslaved in Egypt because Abraham failed to give some non-Jews an opportunity to convert. (Neddarim 32a)
“Rabbi Abbahu said in Rabbi Eleazar’s name: Why was our Father Abraham punished and his children doomed to Egyptian servitude for two hundred and ten years?… R. Yohanan said: Because he prevented people from entering beneath the wings of the Shechinah (converting to Judaism), as it is written, ‘The king of Sodom said to Abraham: Give me the people, and take the property for yourself’ (and Abraham agreed). (Genesis 14:21)
Thus. when Rabbi Yohanan says the Jews were oppressed and enslaved in Egypt because Abraham didn’t try to influence some captives that he rescued to become Jewish; he means that even failing to encourage potential converts is wrong. These are practical, not theological, reasons to seek converts and not to push away those who might be interested.
Rabbis today should welcome potential converts and not discourage them. We may not be saving souls, but by rejecting people who want to be Jewish, we may be making them or their descendants into future enemies, at a potential great cost to our descendant’s.
To see how bad the situation is in Israel think about the following official figures. The state-run ultra-Orthodox controlled Conversion Authority works slowly and bureaucratically, deterring hundreds of thousands of immigrants from the former USSR who have Jewish lineage but who are not Jewish according to Halakhah.
In 2011 the state’s Conversion Authority performed just 4,293 conversions, compared with 8,008 in 2007. From 2008 to 2010, the number of conversions dropped to 4,645 from 6,221. (Rabbi David Stav in The Jewish Daily Forward April 9. 2013) And things have not gotten better since then.