The goals of eugenics fall in two category.

The first one would be: "willfully tweaking the human genetic pool in order to remove its defects", while the other would be: "willfully tweaking the human genetic pool in order to enhance its qualities".

On an ethical point of view, they differ in the way that the first one, removing defect, is a lot easier to justify. But there are some points of the second, enhancing the pool, that should be considered rationally.