I mentioned that before 40 days from the moment of conception there is not a question of murder.
There are, however, opinions among the halachic authorities that the meaning of the Talmud which states before 40 days it is not a life, is only concerning the laws of “tumah and taharah,” or ritual purity concerning entering the Temple in Jerusalem, but for other matters such as murder it is considered a life from conception.
Even according to the first, majority opinion, this does not mean there is no halachic discussion of the status of the embryo before that time. Even if that fledgling life does not yet fall under the category of life to be liable for murder; the embryo, which carries within it the God-given potential for receiving life, is already considered a holy thing. Only severe physical or mental health related issues would be considered by an halachic authority as grounds for terminating such a divine life-potential. Such rulings are rendered on a case-by-case basis.
Many factors are taken into account before rendering such a ruling, all with a grave reverence for the life-potential at hand, and for He who has endowed that soon-to-be full life. It is considered by halachic medical ethicists to be far more than a biological consideration.
I have not come across any rabbinic discussion as to the status of one who would have killed Adam before he was endowed by a soul. (This would have technical difficulties, as there wasn’t yet anyone else around to kill him.)
What is described in the Midrash and Talmud is the profound handiwork of the Almighty in forming the first human being. Like the embryo, the first man was part of the miraculous handiwork of God, a receptacle for a soul which a spark of the Almighty Himself.
We need to think long and hard about before we would do anything to interfere in that receptacle’s reaching its potential and terminate the life of a fetus.
Rabbi Yerachmiel Fried