Society holds the viewpoint that it is wrong to attempt to create better humans (through Eugenics). That is, we shouldn't play god. Medicine goes against natural selection, and therefore it is playing god. It theoretically also makes evolution stall, and makes our species as a collective whole, weaker. So, is medicine right?

One of the reasons that eugenics has often been considered disreputable is that the criteria for "better" humans have been considered arbitrary or worse. But if we could implant a component in our genes that would give us immunity to some dread disease (like those for which we now have vaccines), then I doubt that the standard objections to eugenics would apply to it. The objections to eugenics are not that it goes against natural selection -- as if there were something especially morally significant about natural selection. There is not. After all, the preferences that we express in choosing certain people rather than others as our mates exercises a selection pressure but is not morally problematic. One way to see the potential problems with eugenics arises just with my comment above -- where I referred to a dread "disease." Surely, you might say, we can all agree that genetic manipulation for the elimination of disease would be worthwhile. But what counts as a disease? At one time, a slave who was...