Thomas Aquinas

“ Now it is evident that in the opinion of philosophers, the active principle of generation is from the father, while the mother provides the matter. Therefore original sin, is contracted, not from the mother, but from the father: so that, accordingly, if Eve, and not Adam, had sinned, their children would not contract original sin: whereas, if Adam, and not Eve, had sinned, they would contract it. ”

“ Further, whatever is transmitted by way of human origin, is caused by the semen. But the semen cannot cause sin, because it lacks the rational part of the soul, which alone can be a cause of sin. Therefore no sin can be contracted by way of origin.
Objection 4: Further, that which is more perfect in nature, is more powerful in action. Now perfect flesh cannot infect the soul united to it, else the soul could not be cleansed of original sin, so long as it is united to the body. Much less, therefore, can the semen infect the soul. ”

“ Yet if we look into the matter carefully we shall see that it is impossible for the sins of the nearer ancestors, or even any other but the first sin of our first parent to be transmitted by way of origin. The reason is that a man begets his like in species but not in individual. ”

“ Although the guilt is not actually in the semen, yet human nature is there virtually accompanied by that guilt.
Reply to Objection 4: The semen is the principle of generation, which is an act proper to nature, by helping it to propagate itself. Hence the soul is more infected by the semen, than by the flesh which is already perfect, and already affixed to a certain person. ”

“ Therefore we must explain the matter otherwise by saying that all men born of Adam may be considered as one man, inasmuch as they have one common nature, which they receive from their first parents; even as in civil matters, all who are members of one community are reputed as one body, and the whole community as one man. ”

“ Original sin is taken away by Baptism as to the guilt, in so far as the soul recovers grace as regards the mind. Nevertheless original sin remains in its effect as regards the "fomes," which is the disorder of the lower parts of the soul and of the body itself, in respect of which, and not of the mind, man exercises his power of generation. ”

“ In endeavoring to explain how the sin of our first parent could be transmitted by way of origin to his descendants, various writers have gone about it in various ways. For some, considering that the subject of sin is the rational soul, maintained that the rational soul is transmitted with the semen, so that thus an infected soul would seem to produce other infected souls. ”

“ Wherefore granted that the rational soul were transmitted, from the very fact that the stain on the child's soul is not in its will, it would cease to be a guilty stain binding its subject to punishment; for, as the Philosopher says (Ethic. iii, 5) , "no one reproaches a man born blind; one rather takes pity on him." ”

“ God . . . jealous, visiting the iniquity of the fathers upon the children, unto the third and fourth generation." Furthermore, according to human law, the children of those who are guilty of high treason are disinherited. Therefore the guilt of nearer ancestors is also transmitted to their descendants.
Objection 2: Further, a man can better transmit to another, that which he has of himself, than that which he has received from another: thus fire heats better than hot water does. Now a man transmits to his children, by the way, of origin, the sin which he has from Adam. ”

“ Consequently those things that pertain directly to the individual, such as personal actions and matters affecting them, are not transmitted by parents to their children: for a grammarian does not transmit to his son the knowledge of grammar that he has acquired by his own studies. ”

“ A man can more easily transmit that which he has of himself, provided it be transmissible. But the actual sins of our nearer ancestors are not transmissible, because they are purely personal, as stated above. ”

“ Others, rejecting this as erroneous, endeavored to show how the guilt of the parent's soul can be transmitted to the children, even though the soul be not transmitted, from the fact that defects of the body are transmitted from parent to child---thus a leper may beget a leper, or a gouty man may be the father of a gouty son, on account of some seminal corruption, although this corruption is not leprosy or gout. ”