Part 1  The situation for the Lutheran Church is very different than in Catholicism and probably different than in the Presbyterian church as well.    The Augsburg Confession, the primary document of Lutheran doctrine and teaching from the reformation period,  has a very simple statement on the role of the minister:  Article XIV says simply:  "It is taught among us that nobody should publicly teach or preach or administer the sacraments in the church without a regular Call."

The picture of the role of clergy as it has evolved in the Lutheran Churches (esp. ELCA, which I am a Pastor of) is that there is a dynamic among the concept of the priesthood of all believers, which grants every believer priesthood, and the public role exercising this vocation.  The modern church does require ordination by qualified candidates who have prepared, usually through seminary, although we do have a non traditional route, too (BTW:  I recommend the book Pastrix) by a woman pastor ordained this way.