A woman cannot act in persona Christi - in the very person of Christ - as a priest is called to do sacramentally. There is a fundamental difference in gender. It is simply a false modern construct to say there is not. God created us man and woman for a reason. If everybody's role is the same why two genders? And who is to say a woman's role as traditionally understood is not valuable and important in its own way? The Church is right on this one, and that's ultimately all that matters.