"The Chosen people of the Old Covenant did not establish the Jewish priesthood. It was established by the Supreme Being who limited the priesthood to males of the tribe of Levi. Did God then unjustly discriminate against members of the other eleven tribes, both men and women? Shall we accuse God of sin? What an absurdity! God picks his priests, and they serve at his pleasure. When Korah and other non-Levites tried to perform priestly rites, Moses warned them. When they continued in their obstinacy, God destroyed them (cf. Nm 16).
Christ on earth established the Catholic priesthood, the priesthood of the New Covenant. Man had no more say in this than in the Levitical priesthood. Christ purchased the right to set the laws and limits for his sacraments, including Holy Orders, with his own blood on the Cross.
Christ chose only males to be Apostles. Why?
Advocates of priestesses say that he bowed to cultural limitations, to deep-seated, ancient male chauvinism. I wonder how many understand the arragance of this idea. Imagine the absurdity of accusing Jesus Christ of the sin of sexism! Or, if he was not a sexist himself, but tolerated sexism in deliberately choosing only male apostles, then he compromised with and fostered this sin. To believe such arguments is to deny the Incarnation, the essence of the Christian faith.
The issue today is not whether the Church will have priestesses. She won't. The only open issue is whether the would-be priestesses will have the Church. The issue is not theoretical but practical; it is a test of loyalty to the Church, and therefore to Christ. For the Head is not related to his Body as a CEO to a business, but as the furry ball between your shoulders to your torso. To say yes to Christ but no to his Church is to will a divine decapitation."
-Peter Kreeft, from the book Women and the Priesthood.