Question re immaculate conception

My Orthodox friend says that the RCC teaches that original sin is transmitted via the sexual act. Really?

If that’s so, then why would there need to be a doctrine of the immaculate conception–since Jesus was not conceived via the sexual act?


Pope Pius IX defined the doctrine of the Immaculate Conception in the Apostolic Constitution Ineffabilis Deus:

We declare, pronounce, and define that the doctrine which holds that the most Blessed Virgin Mary, in the first instance of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Savior of the human race, was preserved free from all stain of original sin, is a doctrine revealed by God and therefore to be believed firmly and constantly by all the faithful.

The doctrine of the Immaculate Conception refers to the Virgin Mary, not Jesus Christ.


The Catholic Church does not teach that the original sin is transmitted sexually. Original sin is transmitted by the mere fact that we are human. How it is done is a mystery. As the CCC states:

404 How did the sin of Adam become the sin of all his descendants? The whole human race is in Adam “as one body of one man”.293 By this “unity of the human race” all men are implicated in Adam’s sin, as all are implicated in Christ’s justice. Still, the transmission of original sin is a mystery that we cannot fully understand. But we do know by Revelation that Adam had received original holiness and justice not for himself alone, but for all human nature. By yielding to the tempter, Adam and Eve committed a personal sin, but this sin affected the human nature that they would then transmit in a fallen state.294 It is a sin which will be transmitted by propagation to all mankind, that is, by the transmission of a human nature deprived of original holiness and justice. And that is why original sin is called “sin” only in an analogical sense: it is a sin “contracted” and not “committed” - a state and not an act.?

Also the Immaculate Conception is in regards to Mary being conceived and free from original sin, not Jesus. There are other threads that discuss this if you are interested.

Thomas Aquinas held that it was passed on by the seed of men (sexually), but that is not an official Church teaching.

The Immaculate Conception refers to Mary’s birth, not Jesus’.

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit