None of us are new souls; we all have accumulated experiences from previous lives in other incarnations. In each generation over the past six thousand years, souls have descended that were here on previous occasions. They are not new souls, but souls of a different kind that attained some form of spiritual development.
Souls descend to earth in a special order: They enter the world cyclically. The number of souls is not infinite; they return again and again, progressing toward correction. They are encased in new physical bodies which are more or less the same, but the types of souls that descend are different.

Courtesy of http://www.youtube.com/watch?v=TVboOdX9icA