This is an important question concerning the legitimacy of celibacy in the Sacrament of Holy Orders. I, for one, am a believer in the Catholic faith, and a devout supporter of the discipline of celibacy for bishops and priests. This discipline can, however, be changed by the Church, as it is different from a dogma/doctrine of the Church. However it is a discipline that I am strongly in favor of, for reasons I will list below.
First of all, let me say that I am in agreement with the previous posts which said that, the verses 1 Timothy 3:1-6 are not teaching that bishops have to be married. It is only teaching that a bishop can only be married once, and not have multiple wives. There is a big difference between saying that, and saying that all bishops must be married. Also, let me just say that there have been Catholic priests and bishops who were married, some having converted to Catholicism from a denomination which allowed them to be married and still serve in their office of priest/bishop. The Church welcomes them with open arms into the One, Holy, Catholic, and Apostolic Church so that they can serve the Lord in their full capacity as members of the Church’s hierarchal priesthood/episcopate, while still remaining married. However this does not mean that the Church wishes to choose all of It’s priests and bishops from among men who are already married, and with good reason.
First, let me add that the Catholic Church does not force celibacy on anyone, whether laity or those who are considering becoming a part of the ecclesiastical ministry. She does however normally choose bishops and priests from among men who have already taken a vow of celibacy before God. Also, no one has a right to take part in the Sacrament of Holy Orders, it is a calling from God. It is the Church Herself who has the right to call men to take part in this Sacrament, and thus can choose whom She deems most worthy, which would be those who have already taken a vow of celibacy. Let me quote from the Catechism of the Catholic Church:
1578 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.69 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.
1579 All the ordained ministers of the Latin Church, with the exception of permanent deacons, are normally chosen from among men of faith who live a celibate life and who intend to remain celibate "for the sake of the kingdom of heaven."70 Called to consecrate themselves with undivided heart to the Lord and to "the affairs of the Lord,"71 they give themselves entirely to God and to men. Celibacy is a sign of this new life to the service of which the Church’s minister is consecrated; accepted with a joyous heart celibacy radiantly proclaims the Reign of God.72
69 Cf. ⇒ Heb 5:4.
70 ⇒ Mt 19:12.
71 ⇒ 1 Cor 7:32.
72 Cf. PO 16.
vatican.va/archive/ENG0015/__P4X.HTM
The reasons for the Church choosing men who have already taken a vow of celibacy for the Sacrament of Holy Orders should be obvious. A man who is unmarried does not have the family concerns and issues that a married man has, and thus he can focus more of his time and attention on things concerning the Lord. Saint Paul himself tells us this in 1 Corinthians:
1 Corinthians 7:32 I should like you to be free of anxieties. An unmarried man is anxious about the things of the Lord, how he may please the Lord.
1 Corinthians 7:33 But a married man is anxious about the things of the world, how he may please his wife,
1 Corinthians 7:34 and he is divided. An unmarried woman or a virgin is anxious about the things of the Lord, so that she may be holy in both body and spirit. A married woman, on the other hand, is anxious about the things of the world, how she may please her husband.
Earlier in chapter 7 of 1 Corinthians, Saint Paul also says that he wishes for the unmarried and widows to remain as he was, that is single:
1 Corinthians 7:8 Now to the unmarried and to widows, I say: it is a good thing for them to remain as they are, as I do,
Also, in the Gospel of Matthew we find Jesus explaining to the Apostles that there are some who have renounced marriage for the kingdom of God:
Matthew 19:12 Some are incapable of marriage because they were born so; some, because they were made so by others; some, because they have renounced marriage for the sake of the kingdom of heaven. Whoever can accept this ought to accept it."
Jesus also taught that whoever can accept this (celibacy) should accept it. He not only approved of such personal sacrifice for the sake of the kingdom, He encouraged it.
From the context of these verses, we see that celibacy is a specific calling from the Lord for men (and women) to answer so that they can more fully devote their entire lives to serving God. This is especially so in the case of the Sacrament of Holy Orders, for bishops and priests are better able to shepard their flocks due to the fact that they are unmarried and can devote their entire lives to serving the Church.
Again though, no one is forced to reject marriage, as that would be against the teachings found in Sacred Scripture:
1 Timothy 4:3 They forbid marriage and require abstinence from foods that God created to be received with thanksgiving by those who believe and know the truth.
That is why the Church says that It does not forbid marriage for bishops and priests, but that It normally chooses men who have already taken a vow of celibacy to become bishops and priests through the Sacrament of Holy Orders.
I hope that helps.
May God bless you and Mary keep you in her prayers always.
YinandYang