According to Roman Catholicism, at what point does original sin affect the human soul? CCC 366 teaches that every soul is immediately created by God and not produced by the parents.

The Church teaches that every spiritual soul is created immediately by God - it is not &quot;produced&quot; by the parents

CCC 365 states that soul and body are not two separate aspects of man but form an inseparable unity

in man, are not two natures united, but rather their union forms a single nature.

CCC 404 says that original sin is transmitted by propagation, through the parents, of a deprived human nature

Adam and Eve committed a personal sin, but this sin affected the human nature that they would then transmit in a fallen state. 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.

If human nature is an inseparable unity of body and soul and, if original sin is passed through a deprived human nature, then it must be concluded that, in human nature both body and soul are equally deprived.  If God immediately creates each soul, what is it's state at the moment of it's creation:  Is it A) created already deprived or does it B) share equally in the deprivation of the flesh once united with it?
If A, which I doubt will be the answer, then original sin is imparted to the soul at creation rather than inherited.
If B then it is actually the flesh only that transmits original sin.
Is there a third logical option that this question is missing?
Human soul created and united to the body simultaneously
Pope Pius IX, in his dogmatic definition of the Immaculate Conception, Ineffabilis Deus, stated that the Blessed Virgin Mother's soul was free from original sin

in primo instanti creationis atque infusionis in corpusin the first instant of [its] creation and infusion into (union with) the body

&quot;Creation&quot; and &quot;infusion&quot; are simultaneous.
&quot;Instanti&quot; here is the singular ablative of &quot;insto&quot; (instant); there is one instant (not one for creation and another for infusion
This is St. Thomas's teaching, too (Summa Theologia I q. 118 a. 3 co.):

we must simply confess that souls were not created before bodies, but are created at the same time as they are infused into them.simpliciter confitendum est quod animæ non sunt creatæ ante corpora, sed simul creantur cum corporibus infunduntur.

Thus, since there is no duration of time between the soul's creation and union with the body, there is no immaculate soul first and later, once united to the body, a soul stained by original sin.
This doesn't mean God taints the soul with original sin when He creates it, though; God is not a cause of sin.