"Note that the Iranian stem cell research, which greatly exceeds that of the West, is based on embryonic sources. [The Imans for these particular Moslems hold that, until the embryo achieves 90 days, it is not a person. Similar views were promolgated by Augustine & Aquinas.] "
Responding to another subscriber later on he continues:
"To fisherman: To the contrary, Augustine and Aquinas lived in societies where crude abortion and infantcide was rampant. Augustine also practiced birth limitation by coitus interruptus for 15 years in his first relationship.
Who are we to say when God infuses the fetus with a soul and it becomes a human? We can only speculate and there is no infallible Catholic dogma as to when that infusion occurs. Genesis seems to indicate that this occurs when the infant first breathes air.
Needless to say his comments do not contribute to the greater glory of God (ie AMDG).
Let’s first discuss the question of the infusion of the soul. Before we begin we need to define what the world "soul" means in philosophy. The soul is the life principle of a body. So if a body is living it has a soul. This means that plants and animals have souls. People who come across this statement for the first time (without knowing what the definition of the word "soul" is) are often quite surprised to hear this and may even think it equates to some sort of paganism or pantheism until it is explained properly. I can’t speak for hUMPTY dUMPTY’s knowledge but his comments make the assumption that soul = human. In matter of fact a plant possesses a vegetive soul, an animal a sensitive material soul and a man a spiritual soul. (When we say an animal’s soul is "material" we do not mean "made of matter" but that it’s existence is dependent on its senses. Once the body dies the soul ceases to exist.)
Having laid some groundwork we can see that to determine whether the subject in question has a soul all we need to do is ask one simple question "is it alive in and of itself?" Clearly the answer as to whether the so-called "fetus" is alive is ‘yes.’ Dead things do not grow for one thing. The other question is whether it is a unique living subject in itself. My hand for instance is alive but is part of me and doesn’t have a soul all of its own. Here the only alternative is that it is part of the mother. As we know from modern science it possesses its own unique DNA code and hence cannot be the same individual as the mother (ie a ‘part’ of her).
I want to pause at this point to note that the arguments in the above paragraph are concerned with what the abortion "debate" centres around and I don’t intend to go into to much detail on that here. I only bring it up to get to my main point, which is this:
The question is not about when the child ("fetus") first has a soul (at the very least for when Catholics discuss the question ). The question is when does it first have a spiritual soul. Aquinas did hold contrary to the assertion made above that the unborn had a soul from the moment of conception but (due to the influence of the biology of his day) he held it to at first be vegetative, then sensitive and finally spiritual. The question was not "did it have a soul" but "what type of soul did it have at any one point of development."
The Catholic Encylopedia gives a good overview of St Thomas’ teaching on the soul. See especially the last point:
St. Thomas's doctrine is briefly as follows:
the rational soul, which is one with the sensitive and vegetative principle, is the form of the body. This was defined as of faith by the Council of Vienne of 1311;
the soul is a substance, but an incomplete substance, i. e. it has a natural aptitude and exigency for existence in the body, in conjunction with which it makes up the substantial unity of human nature;
though connaturally related to the body, it is itself absolutely simple, i.e. of an unextended and spiritual nature. It is not wholly immersed in matter, its higher operations being intrinsically independent of the organism;
the rational soul is produced by special creation at the moment when the organism is sufficiently developed to receive it. In the first stage of embryonic development, the vital principle has merely vegetative powers; then a sensitive soul comes into being, educed from the evolving potencies of the organism -- later yet, this is replaced by the perfect rational soul, which is essentially immaterial and so postulates a special creative act. Many modern theologians have abandoned this last point of St. Thomas's teaching, and maintain that a fully rational soul is infused into the embryo at the first moment of its existence.
As an aside this is what caused St Thomas to err on the matter of the Immaculate Conception, however, he did hold that Mary was free from sin right from the first moment she did possess a spiritual soul.
Furthermore he would not have approved as morally licet the killing of the child at any stage as this would then be the sin of contraception.
Now, let’s move on to the second point having identified the correct question viz what does Catholic dogma have to say about the time of the infusion of a rational spiritual soul? Here it is true that there is no specific Catholic dogma defining this. However, as of 1854 it is a necessary presupposition of another dogma, id est, the Immaculate Conception. No Catholic can hold that the soul is not spiritual at the moment of conception and be a Catholic at the same time for it would be impossible to assent to the above dogma according to the sense in which the Church has defined it if one did so.
To conclude this post let’slook at his last point.
The reference to Genesis is flawed. It does not say one receives a soul the moment you take your first breath. Rather it says:
"And the Lord God formed man of the slime of the earth: and breathed into his face the breath of life and man became a living soul."
So it is the Lord God who does the "breathing" and what he breathes into man is the "breath of life" which is simply a descriptive synonym for the word "soul." Calling it the "breath of life" doesn't mean one has to be breathing to have one.
 I say "at the very least for Catholics" as this isn't a matter that is the exclusive domain of Church doctrine.