Answers to Quora Questions by Yair Davidiy
https://www.quora.com/You-just-found-out-with-certainty-that-your-mother-is-not-Jewish-What-would-be-your-reaction-and-how-would-you-conduct-your-life-moving-forward/answer/Yair-Davidiy
Background: Jews are curious people. Religious Jews are taught to be curious and encouraged to ask questions. They are also concerned with people and like to know about those they are involved with. There are a few who sometimes exceed good taste in these matters. One may need to set limits. This is especially the case with Hasidim but Litvaks can also be like that. That is what makes the following true incident surprising.
The Incident: A student studied at a Litvak Yeshivah in the USA. He then came to Israel and also studied there at another major Litvak Yeshivah. After that, I understand, he went back to the USA and continued to learn at Yeshivah level. These institutions have a reasonably high entrance bar. One needs to pass examinations and receive recommendations to be accepted to them. Motivation is also necessary along with good behavior and persistence. A degree of self-sacrifice, dedication, and determination is often involved. -The person spoken about appears to have been well-known. His levels of religiosity and academic achievement were apparently acceptable, perhaps more than that. He wished to get married and had taken steps to do so. Someone, for some reason, made inquiries about his family. It was revealed that his mother was not Jewish and therefore neither was he. Whether he had previously known about this or not is uncertain. The "Rosh Yeshivah" (Head of the Yeshivah) called him into the office and told him the news. He asked if he needed to convert. The answer was he could if he wished to but was not obligated to do so. He decided not to. A popular version of the tale says he took his Kipa (skull cap) off on the spot and walked out.
What they who knew the person found surprising is that the case concerned someone who had been assumed to be Jewish, had assumed himself Jewish, had learned about Judaism at a high level, had already given an important part of his life to Judaism, and could probably have made himself legally Jewish almost on the spot. He would have had very few (if any) of the problems and/or complexes that some other converts have to deal with.
What happened to him after that, I never heard.