Clones will become increasingly inferior, as more copies of the same individual are produced. There's no scientific evidence for it. It's unlikely that clones will be mass-produced. Women have to bear them and someone has to raise them. This is an important point that much discussion about cloning overlooks.
Cloning uses a human being as a means to an end.
Parents have children for many reasons, both selfish and unselfish. Sometimes it may be ethically allowable to conceive a child primarily for the benefit of someone else, as long as the child is loved and cared for as an equal with a family's other children. This has already occurred, when parents of a teenager with leukemia conceived a child as a marrow donor. Consider the following case, which actually happened in the United States. Conceiving a child to benefit a teenager with leukemia.