Jesus established a Church and entrusted the salvation of His followers to that Church.  If the teachings of His Church were changeable or open to a variety of opinion, then how could anyone have any trust in that Church?  Indeed, what would be the point?  It would be like having a group of people sit down and play a board game, but each person is given his own set of rules and instructions, open to individual interpretation.  How can that possibly be fair?  Surely a just and merciful God would not play such a cruel prank on His people as to give them a Church with teachings that are not sure nor certain.

Jesus knew what He was doing when He chose only males to be His apostles, to be the first priests.  The only way one can argue against this is to either claim that Christ did not know what He was doing (thereby negating His divinity), or that the Gospels are lies or errors, in which all Scripture is then suspect, or that the Church is wrong, in which case, why belong to it?