A new study of more than 35,000 adult Americans by the Pew Forum on Religion & Public Life suggests the days of "inherited" religion may be passing; Americans no longer automatically stick to the religion of their parents.

If you include switches from one form of Protestantism to another, 44% of Americans have changed their affiliation or dropped their connection to a faith since childhood. America is still a highly-religious nation--only 4% describe themselves as atheist or agnostic--but religion's hold on individual identity seems to be loosening. Another example: Over a third of married Americans are married to someone of a different faith.

Other findings:

• Protestants make up just 51% of the U.S. population, meaning "that segment of Christianity is close to becoming a religious minority." Young people are helping fuel that trend: While 62 percent of Americans 70 and older are Protestant, only 43 percent of Americans ages 18-29 are.
• Catholics are the religious group with the greatest loss of adherents, with former Catholics making up about 10% of the U.S. population.
• The greatest growth between childhood and adulthood is for those unaffiliated, which includes atheists and agnostics. That category saw an 8% increase, whereas Protestants and Catholics saw declines.