Arthur has explained that this is NOT just a matter of discipline, but a matter strongly connected to doctrine. Perhaps he can explain this again.....
Unlikely to be convincing, since Christ himself selected married men.
Unfortunately Arthur is wrong, as was pointed out in this piece by Dr. Anthony Dragani. While clerical celibacy is frequently claimed to be of Apostolic Origin, especially among trad Catholics, the actual evidence does not support that conclusion.
http://www.freerepublic.com/focus/f-religion/3259705/posts
Dr. Edward Peters has written some good stuff on this issue. Easy to Bing (which I prefer) or Google.
Fundamentally, clerical CONTINENCE is directly linked to Eucharistic Realism.
ALL clerics (deacons, priests, bishops) in the Roman Rite are bound by canon law to the obligation of perpetual, perfect continence.
He “explain” it until he’s blue in the face. It doesn’t mean he’s right.