Adultery and racism are today's big sins, but many other traditionally condemnable vices have fallen off the list in recent years. In fact, some theologians fear the concept of personal sin is almost lost.

When Pope Benedict XVI said at Easter that in the contemporary world, "the notion of sin" is jeopardized, he got some amens from Protestant pastors as well.

Presbyterian Tim Keller still preaches about sin, but with lots of explanation "because the word is essentially obsolete," Keller says. His three New York City congregations are mostly young and single. "They do get the idea of branding, of taking a word or term and filling it with your own content, so I have to rebrand the word sin."

One starting place is what qualifies as sin these days. A survey by Ellison Research shows that 87 percent of U.S. adults still acknowledge the concept of sin, but what is "almost always wrong" is changing:

• Cheating on your spouse? Wrong. (81% call it a sin.)
• Sex before marriage? Not so wrong (45%)
• Racism? Wrong. (74%)