As Frances Robinson put it very well--there was no Apostolic teaching [coming from Jesus] that only men could be priests.  There WERE NO priests in the Age of the Apostles.  Christian communities [celebrated the Eucharist---the Meal] in private homes and they elected their leaders/presbyters themselves.  Often the presbyters were women.

It was only after the days of Constantine, when Christianity became a state religion---that churches began to be built.  It was then, that men and men only were selected to be priests.  

The trouble is, most of the seminaries really don't teach Church history---because the directors don't want any seminarians asking questions about ordained women in early Christianity.

As far as JP II's seminary education, it was conducted in the basement of Cardinal Adam Stefan Sapieda rectory---during the Nazi occupation of [Krakow] and all of Poland. Sapieda was class-conscious and a descendent from Polish nobility, also acted JP II's mentor when he became bishop.