You state something different than Pope Pius XI. And I don’t find issue with what you wrote. If inheritance of original sin is a condition of the soul at creation, then it would seem that the method by which the life, body and soul was created, by the conjugal act or in a petri dish, is of no effect. Which appears different tan what the Pope said in his encyclical.
No, it isn’t different.
He is talking about human generation, the material component of our bodies.
See the Catechism:
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.
405 Although it is proper to each individual,295 original sin does not have the character of a personal fault in any of Adam’s descendants. It is a deprivation of original holiness and justice, but human nature has not been totally corrupted: it is wounded in the natural powers proper to it, subject to ignorance, suffering and the dominion of death, and inclined to sin - an inclination to evil that is called concupiscence". Baptism, by imparting the life of Christ’s grace, erases original sin and turns a man back towards God, but the consequences for nature, weakened and inclined to evil, persist in man and summon him to spiritual battle.
406 The Church’s teaching on the transmission of original sin was articulated more precisely in the fifth century, especially under the impulse of St. Augustine’s reflections against Pelagianism, and in the sixteenth century, in opposition to the Protestant Reformation. Pelagius held that man could, by the natural power of free will and without the necessary help of God’s grace, lead a morally good life; he thus reduced the influence of Adam’s fault to bad example. the first Protestant reformers, on the contrary, taught that original sin has radically perverted man and destroyed his freedom; they identified the sin inherited by each man with the tendency to evil (concupiscentia), which would be insurmountable. the Church pronounced on the meaning of the data of Revelation on original sin especially at the second Council of Orange (529)296 and at the Council of Trent (1546).297
