They used to be known as slackers and are now called "twixters" (between adolescence and adulthood), boomerang kids or "kippers" (kids in parents' pockets eroding retirement savings).
However, the author of a major study says the twentysomething generation has an unfair press.
Prof Jeffrey Jensen Arnett, who gave the TCD Children's Research Centre's annual lecture last night, coined the phrase "emerging adulthood" to describe the changing attitudes of the generation between 18 and 29.
He says that across the developed world, young people are postponing a permanent job, marriage, children and buying a home - events once seen as marking the transition to adulthood.
It is reflected here, where the average marriage age has risen in a decade from 30 to 33 for a man and from 28 to 31 for a woman.
Prof Arnett, a research professor at Clark University in Massachusetts, said the changes are irreversible. "In the last 50 years, the lives of people in their 20s have changed dramatically all over the industrial world. We have traditionally spoken of how people move from childhood into adolescence, young adulthood and then middle age, but these distinctions don't make much sense anymore. What I call emerging adulthood is a time of exploration, independence, flux and possibility."
He believes the present generation are exercising freedoms other generations could not.
"People don't need to get so serious about life at 19 or 20 anymore. It is frustrating and distressing that they are often portrayed as either selfish or miserable. They are not selfish."
Prof Arnett said part of the phenomenon is the increasing number of young adults living at home, often as a result of prolonged periods in education, job insecurity or high house prices.
