http://www.statcan.gc.ca/pub/11-008-...1/9181-eng.htm
The degree of religiosity expressed by Canadians is associated with the religious background of their parents. Of those who say that neither of their parents had a religion, 85% have a low degree of religiosity and 10% have a high degree. In contrast, of those who say that both of their parents had similar religious backgrounds, 32% have a low degree of religiosity and 33% have a high degree. This is consistent with other studies that show religious parents are most likely to pass their religion on to their children and this occurs most often when both parents have similar religious backgrounds.
http://answers.google.com/answers/threadview?id=272042
About 2/3rds stay with the religion in which they were raised. ("Counting Flocks and Lost Sheep: Trends in Religious Preference Since World War II"By Tom W. Smith, Univerity of Chicago)
Survey studies show that the great majority of Americans raised in
particular denomination remain members after they become adults. But
of persons who report that the religious affiliation of their parents
was "none," less than 40 percent remained without a religious
affiliation when they grew up. Thus, the majority of offspring of
"nones" convert to some religion (Kluegel, 1980).