For the Catholic faith when we consider the spirit comes in the fertilized ovum, and where is the reference in the Bible
you will find references in the Bible such as blessing the woomb, barreness as a curse, miracles babies, pregancy, birth, and also in Jeremiah,5:
“Before I formed you in the womb I knew you, before you were born I set you apart; I appointed you as a prophet to the nations.”
But you will not find a definitive answer in the Bible.
in my understanding, st Thomas d Aquin sustained the theory of mediane animation- at 40 days after conception. Such as some muslins.
Nowdays, the position that was presented to me is that, as we don’t know for sure, and we cannot prove the contrary, the child must be protected since conception (=fertilization), and the soul can be influated from this moment.
You might find the National Catholic Bioethics Center pdf article, “Do Embryos Have Souls?” of interest. According to the article, as far as the Catholic Church is concerned, it is still an open question which as yet has no definitive answer, though probably the most popular theological speculation today is that ensoulment with a rational human soul occurs at conception.
According to Catholic belief the Holy Spirit is given at baptism. Still in one case at least, the Holy Spirit came upon John the Baptist in the womb.
The “Catholic Encyclopedia” explains that the Holy Spirit entered John the Baptist when he was in his mother’s womb, when the Virgin Mary came visiting, during the Visitation.
“And it came to pass that, when Elizabeth heard the salutation of Mary, the infant leaped in her womb.” It was at this moment that God fulfilled the promise made by the angel to Zachary ([Luke 1:15] “and he shall be filled with the Holy Spirit, even from his mother’s womb”; in other words, the infant in Elizabeth’s womb was cleansed from the stain of original sin. The fullness of the Holy Spirit in the infant overflowed, as it were, into the soul of his mother."
(In the article “The Blessed Virgin Mary.”
Or do you mean something else besides the Holy Spirit, when you say “spirit”?
Spirit I mean soul.
The Church teaches that the soul is created “immediately” by God.
The Church has never defined the point of ensoulment.
If God knows himself creating a soul when a sperm and ovum unite, fertilization and animation occur; if God does not know himself creating a soul, there is no fertilization happening. “Simultaneity”.
…in a scientific way.
 Human life must be respected and protected absolutely from the moment of conception.
Yes, life begins at conception.
There has not been a pronouncment that declares ensoulment. This is why ensoulment ought not be part of any pro-life debate.
As a practical matter, we make the assumption that the soul can be in the fertilized ovum from the moment of conception. We cannot know that it is not (pace Aquinas), so we have to assume that it could be.
An analogy can be made to hunting safety. It is a fundamental of firearms safety that you must be absolutely sure of your target and what might be behind it. You cannot just say “probably not”.
If we can ever steer the larger society towards the notion that the unborn child at a certain stage of development is a human person whose life is worthy of protection, the question of ensoulment (at least for theists) will most certainly come up. That is when biology will become not so important as theology. Many people attempt to justify early abortion (i.e., after the first missed period) by saying “it can’t be murder because it doesn’t even look like a human being, it’s just an embryo”.
Yes that is true,
and at the same time, the Christian affirmation of human dignity is based on the wholeness of what it means to be human:
Human beings are a unity of body and soul.
We respect the particular dignity of human life because that unity is a participation in the life of God.
And while the Church’s mission is not to parse out the dynamics of that materially, to ignore the fact that human dignity is a participation in the very life of God can allow us to abdicate our responsibility to protect human life.
You see it all the time; the Church’s silence on the moment of ensoulment is incorrectly seen as an open door to abortion.
So we need to keep the both/and in mind: We don’t make pronouncements on events that we can’t possibly know, and at the same time we act with good faith assumptions about God’s actions and God’s will for human beings.
“It’s not ok to shoot blindly into the woods because you think it’s a deer, and you can’t really see if it’s a human being”.
Good faith is good faith.
That’s just it, “the Church’s silence”. It seems that often in pro-life discourse and apologetics, it is implied that ensoulment at conception is the teaching of the Catholic Church. It is not. We just don’t know. Aquinas said 40 days for a boy and 80 days for a girl (what’s up with that?), but that is not doctrine either. But we do know that a separate, unique human life exists from a moment of conception — human cells with unique chromosomes that will grow into a recognizable human person given only time, nutrition, and protection.
I have heard the objection with regard to molar pregnancies and other aberrant conceptions (such as a blighted ovum). Were they ever human persons? Did they have a soul? We don’t know that either.
I am not even going to go into the ensoulment of identical twins. Almighty God has that one covered as well. It’s a mystery.
Perhaps this mystery points us to the obedient respect for human life, without demanding proof that can’t be provided. That requires faith. And obedience and deference to others is really out of fashion, so…