Human cloning is an example of a teaching that is not explicitly defined by either Church Tradition (teachings of Christ and the Apostles) or Holy Scripture. Rather, the current teachings are a matter of interpretation of Scripture’s portrayal of humans as dignified sons and daughters of God. There is not yet an explicit ex cathedra declaration from the Church regarding the issue of cloning. However, that does not mean that Catholics are free to decide their moral position on the matter without consideration of the Church’s statements and encyclicals.
The ancient teaching of the Church regarding sex is that it has two primary purposes that cannot be separated without incurring grave sin. Sex is ordered for the procreation of children between two married spouses and it is also intended to unify husband and wife in matrimonial love (CCC 2360 and Humane Vitae, 12). Cloning violates the marriage act by separating procreation of children from the unifying act of love between husband and wife. Additionally, cloning often involves the creation and subsequent destruction of large amounts of fertilized eggs. This is contrary to the dignity of the human person. Humans are not tools for science or a means to an end no matter how well intentioned the action (such as cloning people to create an organ donor of “spare parts”). The Church states in the encyclical letter Donum Vitae:
Medical research must refrain from operations on live embryos, unless there is a moral certainty of not causing harm to the life or integrity of the unborn child and the mother, and on condition that the parents have given their free and informed consent to the procedure. It follows that all research, even when limited to the simple observation of the embryo, would become illicit were it to involve risk to the embryo’s physical integrity or life by reason of the methods used or the effects induced. (DV 1:4)
It is probable that the Church will issue an encyclical directly addressing the morality of human cloning if the current public debate continues to rage.