In 2000, Jeffrey Arnett, a developmental psychologist, proposed the idea that there is a stage of life between adolescence and adulthood - emerging adulthood. He builds this argument around data showing that 18 to 25 year-olds see themselves as "in-between." They spend these years exploring opportunities in work and love. What they don't do is make commitments to careers, marriages, and families in their early 20s like their parents did. Emerging adulthood appeared on the scene in the 80s (remember St. Elmo's Fire?) and now defines the norm.

What Is It About 20-Somethings gave readers the opportunity to hear arguments for and against delineating a new stage of life. The article attracted a good many comments, blog posts, and op-eds. Henig's article was the most emailed article for days.

Frankly, I was surprised by the reactions, an apt name for which might be - Judgments about 20-somethings and the Appropriately Defensive Reactions 20-somethings Sling Back.

Things got personal. Fast. And 20-somethings lashed back.

Why the negativity about people in their twenties spending more time in education, not marrying in their early 20s, and taking longer to have a child? And why were 20-somethings so offended to be described as emerging adults?

It could be that people interpret emerging adulthood as a period of time-off, a break from real work that real adults are doing. This is not news to Arnett; he's heard this before. In response, after he introduced the theory of emerging adulthood, he confronted and dismissed the myth that emerging adults are Suffering, Selfish, Slackers in a subsequent article. He interprets negative views of 18 to 29 year-olds as youth-bashing. Negative declarations about and judgments of 18 to 29 year-olds might also be interpreted as prejudiced and discriminatory. Or even ageism?

But there are other reasons that might account for some of the grousing.

Like Henig, many of those who responded to the article had first-hand experience trying to figure-out what is going on with 20-somethings. Parents are struggling with questions such as - should I push my 20-something to finish college because it might increase his chances of getting a job, or should I let him do his own thing until he finds his own motivation?

And 20-somethings want to understand their own lives. They, too, question this period of semi-autonomy. They graduated and now they wonder  - why can't I get a job? Why do I have to depend on my parents? How am I supposed to make it on my own?

The issue is this: no one knows what to do with this new-fangled way of growing up. Parents are confused as to whether they should encourage 20-something children to work toward what they know to be markers of adulthood (like this: "stay in school, get a job, find the right person, settle down and have a family.... ") OR....should they embrace and support, and even encourage them to explore before they settle down?

Fully accepting that there is a new stage of development in town requires us to shed 1950s-based expectations of 20-somethinghood. The problem is that we know how to steer emerging adults to get a "good" job (they're the ones that require a suit and tie and give prizes when you stick around a long time) and have a "good" family. But, we're not so good at knowing how to help emerging adults explore and find themselves.

Not knowing what to do can be stressful. Confusion, worry, fear, anger, and yelling are all relatives so it's easy to understand why having a road-map to these years would make holiday dinners a lot easier.

The theory of emerging adulthood doesn't provide information about individuals. The theory doesn't describe any 20-something you know or will ever know. Rather, the theory provides information about a group of people who share the same age, people associated by the lowest common factors connecting them.

Knowing what an emerging adult shares in common with other emerging adults tells you only a little bit about your son or daughter, or yourself if you are a 20-something. Each emerging adult is a sum of a great many parts, organized in a just-so way. Not only is each 20-something unique in what he or she brings to the 20s, but emerging adulthood is a life stage that treats each 20-something differently. Just as each child experiences his family differently from his siblings, so to do emerging adults experience a stage of freedom.

Does this sound disappointing? Were readers wanting more answers? Some guidance? If so, know this-we have to wait. We need to take our time. As with anything, caveat emptor. In this case, "just say no" to The Idiots Guide to Emerging into Adulthood.

Science takes a long time. We've only just begun. We have to generate new theories, theories will compete, and scientific studies will refine what we know.

Right now we don't know much about how life turns out when 20-somethings explore before they commit. Some expect that we'll see fewer midlife crises; we'll see fewer divorces, and fewer convertibles and PT Cruisers. Others predict that penalties of delayed self-sufficiency will result in some real bad stuff for society, like whole generations of narcissists who refuse to raise needy little children.

We'll see.

Before we commit to a new view of adulthood, this is our time to explore. We have a lot to think about. We can't just rush into a definition we'll have for the rest of our lives. We can't just choose one definition of "adult" that we are going to live with, every day, and share a bathroom with until we die. That's like...forever.