Your jejeune attempt at sarcasm has failed, dear brother.
"You had good reason to be horrified at the thought that another birth might issue from the same virginal womb from which Christ was born according to the flesh. For the Lord Jesus would never have chosen to be born of a virgin if he had ever judged that she would be so incontinent as to contaminate with the seed of human intercourse the birthplace of the Lords body, that court of the eternal king."Yes, it is natural and proper for husband and wife to have sexual relations, but there are appropriate and inapproprate places for that intercourse. just because a given bodily function is natural doesn't mean it's always and everywhere okay to perform it. Urination is natural and proper, for example, but there are appropriate and inappropriate places to urinate. Even though a crucifix is only a piece of wood or metal, it's still a symbol of and reminder of our Lord; no Christian would ever piss on a crucifix!-- Pope Siricius I, "Letter to Bishop Anysius", A.D. 392
Mary's body and soul were immaculate, made so by the Christ she carried within her. What sort of holy man would St. Joseph have been if he'd wanted to impregnate a womb that had one held God Himself? It would be worse than pissing on a crucifix; it would be an act of carnal desire performed upon the Ark of the Covenant itself.