A church without a strong Youth component is a dying church

It is said that a church without a vibrant Youth component is a dying church. No prizes for those who agree. However, if we do not recognise the urgent need to develop and nurture the next generation of worshippers, we could be faced with a very empty church in the not-to-distant future (and some say that we already have parishes with very small numbers attending on a Sunday!).
Therefore, are our existing Church leadership equipped enough to build a younger congregation? Can an ordinary parish exist without a Youth Pastor? How important is it to have a full time Youth worker in every parish to help build the next generation of worshippers?
What should our priorities be in this regard?

WHO ARE THE YOUTH IN THE CHURCH?

If you could describe or define Youth as it pertains to Youth Ministry - who are we talking about? Are there clear criteria which defines the Youth? Do you have suggestions?
I have been amazed at the various opinions and perceptions of who the youth are and what they represent. One of the interesting observations is that some think that because you are not married, you would still qualify as "youth" (regardless of your age) and would be entitled to attend "normal" youth meetings and ministries.
Is age (or age groups) a defining criteria for describing youth or "categories" of youth? Are there any other criteria?
What do you say?