You have a lot here right now. You may want to break the questions into separate threads, or look around at CAF. I am not the best at pro-life apologicts, but I will try my hand here.
As far I know Roman Catholic Church is pro life and it considers that life begins with fertilization.
Yes. The Catholic Church is pro-life. From conception till natural death. (see the CCC)
Anyway What is the scientific proof of it?
Here is a link that describes fetal development.
From the moment of conception, the baby has its own unique DNA, and immediately begins to divide cells. By week 3 of gestation, the heart, brain and spinal cord are formed. And soon after the heart begins to beat.
So here we have a creature with its own DNA, its own heart-beat, and by week 5, cranial nerves are present. This creature is living. Its DNA is human. It is a living, and growing human.
What Eastern orthodox Churches teaches about it?
I am not Eastern Orthodox. So I do not know exactly.
Are rape victims allowed to abortion before fetal stage, or not?
No. Abortion for any reason is wrong. Yes the woman who has been raped is a victim, and more than likely does not want to carry the baby that resulted from their trauma to term. But, the child is an innocent human being. Why would anyone kill an innocent human for the crime of their father?
If not then what would happen if a married women is rape victim,or a child?
They would carry the child to term, and either raise the child themselves with their husband/parents, or place the child up for adoption.
Why they must carry the lifeless fertile ovum( scientific), and then make it a real baby?
Because there is no reason to kill a child for the crime of the father.
And for married women, why husbands will accept it?
It all depends on the husband and wife. If the man truly loves his wife, he will help her heal from her rape, and then each couple will decide to either keep the child, or place it up for adoption.
And after all before fetal stage , even it does not kick, so how is it possible that life begins with fertilization?
I don't know what you mean by this. Around week 5, babies do begin to move, and during week 6, the hands of the baby move. The child is now 1 1/2 months along. By this time, a woman would have missed her period. This means, that between now and 12-13 weeks, most abortions are performed.
Here also is a great video that puts a good perspective on abortion.
I hope I could be of help.
In Christ through Mary,