The statistic was startling: A study of the Jewish community in Greater Boston asserted that 60 percent of the children in interfaith families are being raised as Jews.
The recent Brandeis University study's number was so significantly higher than the fraction found in other studies around the nation, that Jewish community leaders here decided to push a little further in an effort to find out just how Jewish those children are.
Their findings, being released this week, offer a mixed picture.
The interfaith couples who said they are raising their children in the Jewish tradition were remarkably similar to couples who are both Jews: They observe Shabbat, light candles for Hanukkah, and their children have bar and bat mitzvah ceremonies as often as those with two Reform Jewish parents.
But the interfaith couples also differ. They are more likely to have a Christmas tree in December and less likely to send their children on trips to Israel. They join synagogues later and leave earlier.
They are less likely to belong to Jewish community organizations, and their children are less likely to continue Jewish education beyond the bar mitzvah.
The findings offer fodder for an ongoing debate within Ju daism about the impact of intermarriage, which is rapidly and dramatically reshaping the American Jewish community. Scholars say that soon there will be more Jewish children in interfaith families than in families with two Jewish parents.
"Intermarriage has been an enormously controversial issue within the Jewish community," said Christopher Winship, a professor of sociology at Harvard University, who converted to Judaism after marrying a Jewish woman. "Intermarriage has often been claimed to be a disease that's slowly going to wipe out the American Jewish Community, but now you've got to do the math, and you see that if all the Jews that intermarried raised committed Jewish children, we could double the size of the Jewish population in one generation."
The study was funded by the Combined Jewish Philanthropies, which advocates the view that inclusiveness is the only path forward for the Jewish community. CJP spends about 1 percent of its budget annually on programming for interfaith families - well ahead of what most Jewish federations around the nation spend - and sees the study as vindication of its programming decisions.
"We have an opportunity to reach people with a culture and a religion that is attractive, and if we're welcoming and create communities that are purposeful, many more interfaith families are likely to walk in than we thought," said Barry Shrage, the president of CJP. "Of course there are going to be differences, but the news is so much better than anybody thought."
At many Reform synagogues today, half or more of the congregants are interfaith families, rabbis say. And although many rabbis will not officiate at interfaith marriages, because they don't want to signal approval of the phenomenon, interfaith families are largely integrated into other aspects of synagogue life.
"If there ever was a time when there was a stereotypical Jewish family, that time has long gone, and the reality in the Jewish community today is that Jewish families come in every possible shape and size, and it's our responsibility to be open and inviting to them and encourage them to make Jewish choices," said Rabbi David S. Widzer of Temple Etz Chaim in Franklin. "And when families make that choice . . . wouldn't you know it, they raise kids with strong Jewish identities in families that engage in Jewish rituals and practices."
In the home, however, the reality of interfaith marriages continues to challenge many couples.
"My husband was able to say, 'of course, we'll raise the children Jewish,' but, that being said, we have a Jewish home, but we also have a Christmas tree, because that was important to him, even though it's difficult for me," said Lauren Dorn-Jones, 38, of Bedford. Dorn-Jones is Jewish; her husband, Michael J. Jones, is Protestant, and they are raising their son, Charlie, as Jewish.
Dorn-Jones said she does not feel that her interfaith family is welcome in the conservative synagogue where she grew up, but that the local Reform congregation has been open.
"Most of my friends who were Jewish, both of their parents were Jewish, but it will be different in our house, because Charlie will know what his father is, but he is Jewish," she said. "It's confusing."
For his part, Mike Jones says it has been a struggle.
"I've come a long way to be able to say this, but my son is Jewish," Jones said. "I look at Charlie as Jewish, but also as the child of somebody who is not Jewish."
But confusion that may result from such arrangements, he said, "is not a bad thing, because it brings self-awareness, and allows you to dig deeper into who you are."
Paula J. Brody, director of outreach programs for the Reform movement in the Northeast, said the new CJP analysis suggests that intermarried families who are raising their children Jewish may engage more frequently in some rituals such as lighting Sabbath candles, than families with two Jewish parents, perhaps because their religion is a conscious choice.
And she noted that some intermarried couples who are not raising their children Jewish nonetheless light Hanukkah candles or attend Passover seders, presenting an outreach opportunity.
On the downside, she noted that interfaith families reported they had fewer friends from their synagogues, which, Brody said, is not surprising, given that those families are more likely to also have Christian family and communal connections as well.
One finding that is being seized upon by advocates for interfaith families is that interfaith couples whose marriage was performed by a rabbi are significantly more likely to raise their children as Jews. The study did not establish whether the presence of a rabbi at the wedding caused the couples to raise children as Jews, but Edmund C. Case, the president of Newton-based InterfaithFamily.com, said he saw it as support for programs such as his, which try to make rabbis more available to marry interfaith couples.
That finding is being corroborated by a qualitative study of interfaith families, also being released this week, by the National Center for Jewish Policy Studies at Hebrew College in Newton.
That study includes recommendations that rabbis who will not marry interfaith couples do a better job communicating their rationale to couples.
"We've got to be welcoming and not burying our head in the sand and denying that these people have Jewish connections," said one of the study's authors, Rabbi Zachary I. Heller.
Michael Paulson can be reached at mpaulson@globe.com.
