Do priests ever inquire, if the subject is not brought up first by the penitent, whether married people are using contraception? And if not, why not?
In the 14 years I was with my wife, no priest ever asked me this question. (In recent years, one priest challenged why I was in my mid-40s when my only child was born, but that is another story.)
I realize that Humanae vitae did not come right out and say “contraception is a mortal sin”, but the traditional teaching of the Church is that any sexual act, complete or incomplete, where conception is either rendered impossible or is impossible in the first place, is objectively a mortal sin.
I say “objectively”. The matter itself is mortally sinful. As far as full consent of the will is concerned, it is very difficult to contracept accidentally. And as far as full knowledge is concerned, doesn’t the priest have a duty to instruct the penitent who may up to this point have been ignorant of the teaching?
Let me be clear at this point that I totally accept Humanae vitae and all teachings of the Church, and that even NFP can be used for sinful reasons.