The answer is that Jesus Christ, as God, selected only men. He was not influenced by any cultural situation or other things of His time. He acted in a free manner.
Pope John Paul II:
"1. Priestly ordination, which hands on the office entrusted by Christ to his Apostles of teaching, sanctifying and governing the faithful, has in the Catholic Church from the beginning always been reserved to men alone. This tradition has also been faithfully maintained by the Oriental Churches.
"When the question of the ordination of women arose in the Anglican Communion, Pope Paul VI, out of fidelity to his office of safeguarding the Apostolic Tradition, and also with a view to removing a new obstacle placed in the way of Christian unity, reminded Anglicans of the position of the Catholic Church: “She holds that it is not admissible to ordain women to the priesthood, for very fundamental reasons. These reasons include: the example recorded in the Sacred Scriptures of Christ choosing his Apostles only from among men; the constant practice of the Church, which has imitated Christ in choosing only men; and her living teaching authority which has consistently held that the exclusion of women from the priesthood is in accordance with God’s plan for his Church.”(1)
"But since the question had also become the subject of debate among theologians and in certain Catholic circles, Paul VI directed the Congregation for the Doctrine of the Faith to set forth and expound the teaching of the Church on this matter. This was done through the Declaration Inter Insigniores, which the Supreme Pontiff approved and ordered to be published.(2)
"2. The Declaration recalls and explains the fundamental reasons for this teaching, reasons expounded by Paul VI, and concludes that the Church “does not consider herself authorized to admit women to priestly ordination.”(3) To these fundamental reasons the document adds other theological reasons which illustrate the appropriateness of the divine provision, and it also shows clearly that Christ’s way of acting did not proceed from sociological or cultural motives peculiar to his time. As Paul VI later explained: “The real reason is that, in giving the Church her fundamental constitution, her theological anthropology-thereafter always followed by the Church’s Tradition- Christ established things in this way.”(4)
"In the Apostolic Letter Mulieris Dignitatem, I myself wrote in this regard: “In calling only men as his Apostles, Christ acted in a completely free and sovereign manner. In doing so, he exercised the same freedom with which, in all his behavior, he emphasized the dignity and the vocation of women, without conforming to the prevailing customs and to the traditions sanctioned by the legislation of the time.”(5)