I've been covering pacifism, just war, suicide, euthanasia, cloning, abortion, and capital punishment in my classes, and I've been thinking a lot about the "playing God" argument that arises in all these issues. It also plays a major role in arguments against contraception, which Wink and I treated not too long ago. What exactly is this argument supposed to amount to? The one underlying feature to the different versions I can think of is that somehow God has given us certain responsibilities to do but has withheld from us certain things to do, and it's playing God to do the latter. But which things would those be, and why those things? The different realms God is said to have exclusive rights over have been anything involving when someone might die or come into being, any way to affect the characteristics of someone as they come into being, and other issues related to life and death. A helpful analogy, though, is to consider groups like the Amish who make this argument not just about life and death but about many ways in which we live our life. They apply it to certain kinds of technology, though I've never been able to find a consistent standard behind their choices of which kinds of technology to use and which not to use. Knitting needles and computers are equally human-developed technology. But those of a more moderate persuasion who will still give such an argument seem to me to limit it to these life and/or death issues and to using technology to modify something seen to be fundamental to God's prerogative in giving and taking life (and determining what form such life will take, which is why cloning and genetic engineering are part of this).