Today's teenagers and young adults are far more likely than their parents to believe they're great people, destined for maximum success as workers, spouses and parents, suggests a report comparing three decades of national surveys.

And these so-called Millennials or Gen-Y young people may be heading for a fall when their self-esteem is punctured by reality, says psychologist Jean Twenge of San Diego State University. She examined changes from 1975 to 2006 in yearly surveys, given to thousands of high school seniors by University of Michigan researchers.

Compared with the baby boomers who were seniors in 1975, 12th-graders surveyed in 2006 were much more confident they'd be "very good" employees, mates and parents, and they were more self-satisfied overall, say Twenge and co-author W. Keith Campbell of the University of Georgia. Between half and two-thirds of the Gen-Y teens gave themselves top ratings, compared with less than half in their parents' generation. The report is in Psychological Science.

Boomer parents "are more likely than their parents were to praise children — and maybe overpraise them," Twenge says. This can foster great expectations or perhaps even smugness about one's chances of reaching "the stars" at work and in family life, she adds. "Their narcissism could be a recipe for depression later when things don't work out as well as they expected."

But high self-esteem is more likely to protect them against depression, argues Brent Roberts, a psychologist at the University of Illinois at Urbana-Champaign. His studies of teenagers followed to age 21 found that low self-esteem in high school contributes to becoming more depressed later.

There's also evidence that having optimistic goals leads people to do better, Roberts says. "We don't know what these kids eventually are going to do. Maybe a lot of them will be great workers and better at family life than their parents were."

Still, kids and young adults with big egos could create problems for others, says Roy Baumeister, a psychologist at Florida State University who has studied self-esteem. "Many people who grew up in the '50s say, 'Nothing I did was ever good enough for my parents.' Now we're seeing the pendulum swing, and you hear from coaches and teachers who have been at it a while that kids have become more fragile. They don't take criticism well," he says.

"Thinking you're God's gift to the world is nice for you. It's a little harder for everyone else around you."