if it is true that Mary and Joseph had children as claimed by some christians

There is a saying: For those who believe, no explanation is necessary. But for those who do not believe, no explanation will suffice. Nevertheless I will try to make a clearer statement. I have given my reasons based on scripture, why I believe that Joseph never touched Mary as it would be sinful for him (LV. 19, 20) and he remained chaste as Jesus advocated (MT 19,12b), considering the circumstances leading to his being told by the angel to "not be afraid to take Mary home" as if she were his wife and he her husband to preserve the honor of Mary. Otherwise she would continue through life as a divorcee, which would destroy the plan of God because the messiah could never be born of a disgraced woman. With this consideration in mind, as I have previously said, Joseph, being a God-fearing man, consented to be the protector of Jesus , His own savior, without any thought of having any sexual relationship with Mary, who had been espoused by the Holy Spirit. If he were to sleep with Mary. he would be betraying his mission. Returning to your citations, while at first glance it appears that scripture is telling us that James and Joseph, Simon and Jude are indeed the brothers of Jesus, we must discern that Matthew and Mark are not confirming that these persons are Jesus' brothers, but they are merely quoting the words of an anonymous "THEY", who used the word "brothers" in relation to Jesus. However if we look at MT 27,56, Matthew positively identifies James and Joseph as the son of a certain Mary. And in Acts1,13 Simon and Jude appear as apostles of Jesus. Therefore. they are definitely not the brothers of Jesus. As for the alleged brothers of Jesus in MK 3,21, MT 12,46 and LK 8,19 we should realize that these are parallels and are one and the same event. But in MK 3,1 we read: 'When his RELATIVES heard of this, they set out to take charge of him." So most likely the brothers mentioned therein are the very same RELATIVES looking for Jesus, but not his brothers. And about the brothers mentioned in JN2,12, these are probably the same persons mentioned in JN 2,1 as apostles. From the foregoing explanations, it is obvious that the scriptural verses that you cite to prove that Jesus had brothers are hardly any proof that Mary had children by Joseph. And who knows if perhaps Joseph was indeed a widower who had children by another wife. To tackle your question: Did Jesus advocate abstinence? Yes and no. Jesus did not make any specific statement but I believe it is implied in Jn19,12b: "Let anyone accept this (to be a eunuch for the sake of the kingdom) who can." Consider also the words of Paul (1Co,7,1) "Yes, it is a good thing for a man not to touch a woman"; (vs9) "It is a good thing for them to stay as they are, like me"; (vs38) "The man who keeps his daughter unmarried has done something even better." So, contrary to what you say, it is not a shame for women never to be married, or for nuns to remain virgins, forgoing the benefits of sexual pleasure to consecrate themselves to service, although this may be a gift from God and perfectly acceptable. As for your reference to "hypocrites whose consciences are hardened as though with a red-hot iron who forbid marriage," Paul did not mean to refer to the rule of the Church for priests to be celibate. For your information, during the time of Paul there were Jewish sects, like the Essenes, who did not marry. You may also be unaware of a heretical sect in the 11th century, the Albigenses, who forbade marriage. I apologize for including something you consider irrelevant to the topic. But so are your last two issues.