Where are the younger IT workers?

Had an interesting conversation with another consultant at lunch today. We have both noticed that there are relatively fewer younger IT workers in the field now. We are both 30 years old, and most of the people we work with are about our age or a bit older.

Ten years ago during my co-op days and then immediately after in the first years of my career there were quite a few IT workers in their early twenties. The normal model seemed to be a late-twenties guy as a tech lead, a mid-thirties guy as a PM, then several developers in their early twenties. Maybe even co-ops/interns.

Now...mostly people in their early thirties.

So is it a lack of supply? Does that drive the push to offshoring? Or, has the threat of offshoring caused this? In other words, is a demand issue?