Day 216: Who Receives Holy Orders

No one has a right to receive the sacrament of Holy Orders. Indeed, no one claims this office for himself; he is called to it by God. Anyone who thinks he recognizes the signs of God's call to the ordained ministry must humbly submit his desire to the authority of the Church, who has the responsibility and right to call someone to receive orders. Like every grace, this sacrament can be received only as an unmerited gift. CCC 1578

Today's reading from the Catechism is very short, just 4 small paragraphs on who can receive the Sacrament of Holy Orders. This sacrament is reserved for baptized men called by God. In the West, some want to allow women to be ordained, but such is an impossibility. 

As the Catechism Companion, Vol II notes:

Regardless of an individual bishop's opinion regarding the ordination of women being possible, the Church cannot allow it. Jesus himself instituted the sacraments, so it never comes down to how we would choose for any of them to be celebrated validly. For Holy Orders, "the Lord Jesus chose men" exclusively (CCC 1577)... It may seem unjust that women cannot be ordained, but the true injustice would be to go against what Jesus established. (p. 196)

In the Latin Church, there is also a calling for celibacy, which differs somewhat in the East. As the Catechism Compendium notes:

It is always necessary to be celibate for the episcopacy. For the priesthood in the Latin Church men who are practicing Catholics and celibate are chosen, men who intend to continue to live a celibate life “for the kingdom of heaven” (Matthew 19:12). In the Eastern Churches marriage is not permitted after one has been ordained. Married men can be ordained to the permanent diaconate. (#334)

Finally, the Catechism Companion recommends this good video with Fr. Josh Johnson: