All one may need is a nail clipping or the hair left behind in a comb. But perhaps a deeper problem with human cloning is what it would do to our attitude toward the child. Cloning is the ultimate depersonalizing of human reproduction. That openness, and the unpredictability of how the traits of husband and wife will combine in a new individual, expresses the fact that this child is our equal in human dignity, a new person with his or her own open future. Even if identical twins occur, each of them has this unpredictable combination and this newness.
Cloning is just the opposite.
Children are manufactured in the lab to preset specifications. They do not arise, but are constructed. So dehumanizing is this that some scientists want to use cloning chiefly as way to make large numbers of human embryos for destructive experiments. The radical distinction between divine and human is dramatized in the Book of Genesis when God makes Adam and Eve by His own hands.