Both.
The Apostles Jesus selected were all men, and all held "bishopricks."
Acts 1The apostles were the first bishops, and were all men. Christ had the power to select women bishops, but he did not, despite the fact that many contemporary religions had priestesses. (Bishops are also "priests," which is an english transliteration of "presbyter.")13 And when they were come in, they went up into an upper room, where abode both Peter, and James, and John, and Andrew, Philip, and Thomas, Bartholomew, and Matthew, James the son of Alphaeus, and Simon Zelotes, and Judas the brother of James...
15And in those days Peter stood up in the midst of the disciples, and said, (the number of names together were about an hundred and twenty,)
16Men and brethren, this scripture must needs have been fulfilled, which the Holy Ghost by the mouth of David spake before concerning Judas, which was guide to them that took Jesus.
17For he was numbered with us, and had obtained part of this ministry. 18Now this man purchased a field with the reward of iniquity; and falling headlong, he burst asunder in the midst, and all his bowels gushed out.
19And it was known unto all the dwellers at Jerusalem; insomuch as that field is called in their proper tongue, Aceldama, that is to say, The field of blood.
20 For it is written in the book of Psalms, Let his habitation be desolate, and let no man dwell therein: and his bishoprick let another take.
We also know this through Tradition. There is no evidence of female priests anywhere in 2000 years of Church history, as far as I know.
Most important are the theological reasons for the male priesthood. The priest represents Christ, and in dispensing the sacraments, acts in the Person of Christ. Christ's maleness is not an accident of his human nature, nor is maleness in general an accident of human nature. So when a priest acts in the person of Christ, it is fitting that he be a male.
In sum, the Catholic priest is a representative figure selected according to the conditions of embodied, enfleshed persons in concrete human history. The choice was made from all eternity. The selection of males alone as Catholic priests is a sign (a sacrament, bearing grace) of several important revelations about God: about the Trinity, about the Incarnation, about the relation of Christ and His people, and about the importance of gender differentiation. "If men were angels," James Madison once wrote, "no government would be necessary." If men were angels, priests would not need to be (even could not be) males. But under the conditions of human flesh and actual history, it is a more accurate sign of the interior life of the Trinity, of the Incarnation, and of the relation of Christ to His people if the priest is clearly differentiated and selected as a male rather than as a female. Matter is the principle of individuation, and an emphasis on flesh safeguards respect for human individuality, even as it differentiates humans from angels. The priest is male because gender differentiation is significant to the self-revelation of God in history.
Oh no!!!!
Thanks for the explanation.