A group of young people, generally late teens or early twenties, just starting out in life, at the start of their adult life who generally are well educated and think that they know it all but have no life experience and have led a fairly sheltered life.
Quite often they are in positions of minor power because of the skills shortage. For example, they may have a degree and been thrust straight into a management position from university whereas in the past it would have taken 10-15 years to get to such a position.
They usually dress is designer labels with their hair meticulously preened (the boys too).
They usually believe that they know best in any given situation and will not take guidance from older people who have had experience in the relevant topic or area.
They tend not to relate to older people or those from different backgrounds so tend to stick within their own groups.
A business or government department being run or staffed by a group of young people is referred to as being 'a breakfast club'.
Don't try and tell the Breakfast Club over there know how to run the show, they know how to do it, they read it somewhere.