Excellent question. Here are some issues taught when I was in school in the 1960’s.
I know Augustine was down on the sexual pleasure, but I don’t think it’s anything that the Church at large ever accepted.
Today, of course, the Church teaches both procreative and unitive aspects of marital sex, though of course one of the two must not be sought without the other. That means “procreation only” would actually be just as wrong as “unity only.” I’m afraid I don’t know the history on that one, though.
Unbaptized children go to limbo forever
An extremely common belief, and still a permissible one, but never a teaching of the Church.
Basically, we
don’t know what happens to unbaptized children. We can’t just declare them in Heaven, because then baptism would have no point. Augustine thought they went to Hell, but that was (understandably) unpalatable for a lot of people. So, on the model of the “limbo of the fathers” where the Old Testament saints stayed until the Resurrection, theologians proposed a “limbo of the children” where such souls would spend eternity in absolute natural happiness.
That was the best anyone could come up with for a long time. More recently, the thinking has been that we have placed too many limits on the mercy of God, who is not Himself bound by the sacramental rules He sets down for us. Thus, we may hope that even the unbaptized are granted Heaven, which does away with the need for limbo.
No forgiveness for suicide
Even back then, the three conditions for a mortal sin were understood and taught. The “change” is that we now have a better understanding of human psychology and realize that few if any suicides meet those conditions.
Suicide remains grave matter, so if it were to be done with full knowledge and consent, it would be a mortal sin. It would be unforgiveable not because there is anything particularly heinous about suicide, but simply because the person is already dead and past the point of repentance. (Even in the old days, it was recognized that one who committed suicide by a non-instantaneous method – say, jumping off a bridge – could theoretically “repent on the way down.”)
Child’s life comes before the mother’s in a medical emergency
The teaching is that neither life may deliberately be sacrificed to save the other. It’s possible it was phrased as “child first” because most likely the impulse would be to abort the child and save the mother. Also, the mother may choose to increase the child’s chances at the expense of her own (though she still may not actively commit suicide or solicit her own murder), whereas the child is not able to make such a choice.
Eating meat on Friday was a mortal sin
True, not because there’s anything wrong with meat per se, but because to do so knowingly and deliberately as a Catholic would be to rebel against the God-given authority of the Church.
The immoral act would be “rebellion against the lawful authority God has set up, in a matter that is not sinful” (which remains immoral and always will), not “eating a particular food on a particular day.”
Were these things taught with the approval of the pope or not?
I honestly don’t know. Obviously, the pope cannot personally supervise every Catholic school religion class. At best, he could act like the Supreme Court, making a ruling when a problem is brought to his attention.
The Friday abstinence would obviously have been known and approved of (and followed personally) by popes. Many of them likely believed in limbo as the reasonable hypothesis of the time. Some popes may likewise have held incorrect opinions on the other matters above.
I can tell you that no pope ever proclaimed any of these beliefs as definitively binding on the universal Church.
Usagi