This question is NOT equivalent to the ancient quandary of "when does life begin". Life crystallizes, at the earliest, when an egg and a sperm unite (i.e., at the moment of fertilization). Life is not a potential - it is a process triggered by an event. An unfertilized egg is neither a process - nor an event. It does not even possess the potential to become alive unless and until it merges with a sperm. Should such merger not occur - it will never develop life. The potential to become X is not the ontological equivalent of actually being X, nor does it spawn moral and ethical rights and obligations pertaining to X. The transition from potential to being is not trivial, nor is it automatic, or inevitable, or independent of context. Atoms of various elements have the potential to become an egg (or, for that matter, a human being) - yet no one would claim that they ARE an egg (or a human being), or that they should be treated as one (i.e., with the same rights and obligations). Moreover, it is the donor nucleus embedded in the egg that endows it with life - the life of the cloned baby. Yet, the nucleus is usually extracted from a muscle or the skin. Should we treat a muscle or a skin cell with the same reverence the critics of cloning wish to accord an unfertilized egg? Is this the main concern? The main concern is that cloning - even the therapeutic kind - will produce piles of embryos. Many of them - close to 95% with current biotechnology - will die. Others can be surreptitiously and illegally implanted in the wombs of "surrogate mothers". It is patently immoral, goes the precautionary argument, to kill so many embryos. Cloning is such a novel technique that its success rate is still unacceptably low. There are alternative ways to harvest stem cells - less costly in terms of human life. If we accept that life begins at the moment of fertilization, this argument is valid. But it also implies that - once cloning becomes safer and scientists more adept - cloning itself should be permitted. This is anathema to those who fear a slippery slope. They abhor the very notion of "unnatural" conception. To them, cloning is a narcissistic act and an ignorant and dangerous interference in nature's sagacious ways. They would ban procreative cloning, regardless of how safe it is. Therapeutic cloning - with its mounds of discarded fetuses - will allow rogue scientists to cross the boundary between permissible (curative cloning) and illegal (baby cloning). Why should Baby Cloning be Illegal? Cloning's opponents object to procreative cloning because it can be abused to design babies, skew natural selection, unbalance nature, produce masters and slaves and so on. The "argument from abuse" has been raised with every scientific advance - from in vitro fertilization to space travel.