But when she and her husband sought a divorce last year, she said, the ultra-Orthodox rabbis in charge of the process had some questions. Among them: Did Yael observe the Sabbath? Did she obey the prohibition on sex during and after menstruation?  Dissatisfied with the answers, the rabbis nullified her conversion. Yael did not need a divorce, they ruled, because she had never been married. She had never been married because she had never been Jewish. And because she had never been Jewish, her children were not, either.  "I was in shock. I couldn't believe it," said Yael, 43, who would allow only her Hebrew name to be published out of privacy concerns. Blond, blue-eyed and athletic-looking, Yael is baffled by the ordeal. "My kids grew up Jewish," she said. "They don't know anything else."  Yael's personal trauma has become a cause for Israeli soul-searching over what it means to be Jewish, a term that carries both religious and ethnic dimensions. The case has set off a roiling debate between those who see themselves as saving Judaism and those whose first priority is to safeguard the Jewish state.  On one side are ultra-Orthodox leaders who are using their long-standing dominance of Israel's rabbinical court system -- which has authority over marriages, divorces and conversions -- to tighten restrictions governing who can become Jewish. They see themselves as defending the religious purity of a people who, according to their interpretation of Jewish law, need to live apart from other groups.  Those on the other side are much more concerned with demographics: They believe that at a time when the number of Arabs living between the Jordan River and the Mediterranean Sea is poised to surpass the number of Jews, Israel needs all the converts it can get. This group includes secular Jews, but it is led by the religious Zionists, who form the core of the settlement movement in the occupied territories and who feel it is their duty to populate the biblical land of Israel.  The stakes have escalated since Yael's conversion was tossed out: When she appealed to the High Rabbinical Court of Israel, it not only upheld the original decision but also threw into doubt the legality of thousands of other conversions.  "There is a cultural war going on between various segments of Jewish society," said Benjamin Ish-Shalom, chairman of the Joint Institute for Jewish Studies. A trim man with a philosophical bearing who relishes any discussion of Judaism, he helps administer a government-funded education program for Israelis who need help getting through the rigorous process of conversion.  Over the past two decades, Israel has admitted hundreds of thousands of immigrants from the former Soviet Union, over the objections of ultra-Orthodox leaders who spoke out against allowing non-Jews to enter the country. Many of the immigrants lacked the paperwork to prove their Jewish ancestry. Others had fathers or grandparents who were Jewish, but did not qualify as Jewish themselves because Judaism is passed down through mothers. Until now, ultra-Orthodox leaders have not acted as forcefully to invalidate immigrant conversions.  To Ish-Shalom, facilitating conversion has been good for the converts, good for Judaism and good for the state. "Israel needs people. It needs loyal people," he said.  At the moment, there is rough parity between the Palestinian and Jewish populations in Israel, the West Bank and Gaza, according to Eliyahu Ben-Moshe, a demographer and former deputy director of Israel's Central Bureau of Statistics. Because of a high Arab birth rate, Ben-Moshe said, they are expected to establish a clear majority in the coming decades -- a terrifying prospect for Israeli policymakers as the well of diaspora Jews who are willing to immigrate to Israel dries up.
ASHDOD, Israel -- Yael converted to Judaism in 1992, and for the next 15 years she lived in Israel, celebrating the major holidays and teaching her children about the Jewish faith.