As the great wave of interfaith marriages reaches the child-rearing stage, more parents are facing the difficult challenge of deciding in which religion to raise their children.
Many parents have opted to raise their children in both faiths, leaving the children free to choose which religion to practice as they mature.
But some religious leaders say that requires children to make "an impossible decision," and that fundamental differences in religious beliefs make it impossible for a person to be, for example, both Christian and Jewish.
"Wittingly or unwittingly, the two religions are pitted against one another in competition, and the parents are pitted against one another in competition," says Rabbi James Rudin, director of inter-religious affairs for the American Jewish Committee.
Until now, few religious groups have felt the need to adopt formal policies on the issue. But with the rate of intermarriage continuing to grow, the leaders of the nation's largest Jewish denomination have taken a step in that direction, with a measure aimed at encouraging families to declare a single religious affiliation.
At their national convention last week, delegates of the Union of American Hebrew Congregations approved a resolution recommending that Reform Jewish congregations deny enrollment in their religious schools to children who are already receiving formal religious training in another faith.
"We happen to believe parents should make up their mind and determine which tradition a child should be raised in," said Rabbi Eric Yoffie, president-elect of the group, which has been a leader in outreach to interfaith couples.
Yoffie and other Jewish leaders argue that allowing a child to be brought up in more than one faith could be confusing to the child and, ultimately, psychologically and spiritually damaging as well.
The intermarriage rate among Christians and Jews is rising rapidly and today, half of all Jews in America marry non-Jewish spouses.
Among interfaith couples who have children, 28% bring their children up in the Jewish faith, 31% raise them with no religion, 21% raise them in a religion other than Judaism and 20% raise them with a combination of religions, according to an estimate from the Reform group.
That has resulted in situations that pose theological quandaries for clergy, the group said, such as the young girl who showed up at a synagogue for her bat mitzvah wearing a Christian cross.
Few other denominations have official policies on the education of children from interfaith families. In the Roman Catholic Church, couples are strongly encouraged even before their marriage to raise their children as Catholics, but the final decision is up to the parents, said Robert Colbert, executive director of the Department of Religious Education for the National Catholic Education Assn.
If an interfaith couple chose to give their children religious training in both the Jewish and Catholic faiths, they would be welcomed "with open arms," he said.
The Rev. Jay Rock, co-director of Interfaith Relations for the National Council of Churches, said Protestant churches have not taken a position on the issue although the growth of interfaith couples means more pastors are confronted with the sensitive decision.
"So what are you going to do, tell them their child cannot enroll in church school? Unlikely, very unlikely," Rock said. "If you do, you're likely going to lose that couple."
Rock said he thinks a policy prohibiting children from receiving training in two faiths is shortsighted because many interfaith parents will then choose to raise their children with no religious training.
"It doesn't help anyone. It doesn't help the couple. It doesn't help the child," he said.