About half of Americans either disaffiliate from their childhood faith or change faith at least once in their lives, many in their early twenties, according to a study released Monday by the Pew Forum on Religion and Public Life. American Catholics and Protestants who leave the religion they were raised with tend to drift away slowly over time, frequently because they stop believing devoutly in religious teachings. "Very few people have a 'road to Damascus' moment," said Luis Lugo, director of the study. The reference is to the New Testament account of Paul's revelation that led to his abandoning Judaism for Christianity. The new survey, a follow-up to Pew's landmark 2007 study of the religious views and practices of 35,000 Americans, focused on the behavior of Catholics and Protestants, the largest groups in the original sample pool. It does not draw specific conclusions about other religious groups, including Jews and Muslims. Yet Lugo noted that the ethnic component of Jewish identity means even those who stop going to synagogue or observing holidays tend to continue identifying themselves as Jewish. "There is a strong cultural element to Judaism that keeps many Jews within the broader fold of religious identification, even though Jews rank among the lowest of all Americans in terms of synagogue attendance," Lugo told reporters on a conference call. "If you look at religious practices, you would say Jews are going to disappear, but if you include cultural practices, that's an important element," Lugo added. Steven Cohen, a Hebrew Union College research professor on Jewish social policy who is an expert on Jewish demographics, told The Jerusalem Post that the broad generalizations the Pew study drew about Catholics and Protestants don't apply to Jews, mainly because of the ethnic dimension of the religion. "Very few Jews who are raised Jewish abandon their Jewish identity," Cohen told the Post. Those who do drift away from ritual observance, he said, tend to continue actively identifying themselves as Jewish, while those who do leave the religion tend to do so because of intermarriage, not the slow drift ascribed to Catholics and Protestants. About 46 percent of Catholics who left the faith continued to identify as Protestant, choosing a Protestant denomination, but 38% reported having no affiliation at all. People who were raised Protestant tend to switch to another Protestant denomination, usually because they move or want a different style of worship, with only about a third disaffiliating from religion altogether. Lugo noted that American Catholicism is consistently replenished by immigrants from Latin America, while American Jewry continues to shrink as an overall share of the population. A study released last month by Trinity College found that about 1.2% of Americans identify their religion as Jewish, a drop from 1.8% in 1990.