The answer is negative, for the following reasons:
1. On the basis of a complete biological analysis, the living human embryo is – from the moment of the union of the gametes – a human subject with a well defined identity, which from that point begins its own coordinated, continuous and gradual development, such that at no later stage can it be considered as a simple mass of cells.
2. From this it follows that as a human individual it has the right to its own life; and therefore every intervention which is not in favor of the embryo is an act which violates that right. Moral theology has always taught that in the case of jus certum tertii the system of probabilism does not apply.
3. Therefore, the ablation of the inner cell mass (ICM) of the blastocyst, which critically and irremediably damages the human embryo, curtailing its development, is a gravely immoral act and consequently is gravely illicit.
4. No end believed to be good, such as the use of stem cells for the preparation of other differentiated cells to be used in what look to be promising therapeutic procedures, can justify an intervention of this kind. A good end does not make right an action which in itself is wrong.
5. For Catholics, this position is explicitly confirmed by the Magisterium of the Church which, in the Encyclical Evangelium Vitae, with reference to the Instruction Donum Vitae of the Congregation for the Doctrine of the Faith, affirms: “The Church has always taught and continues to teach that the result of human procreation, from the first moment of its existence, must be guaranteed that unconditional respect which is morally due to the human being in his or her totality and unity in body and spirit: “The human being is to be respected and treated as a person from the moment of conception; and therefore from that same moment his rights as a person must be recognized, among which in the first place is the inviolable right of every innocent human being to life . . .”
