The word Eugenics gives the idea of somebody deciding whether people can have children based on their genes, and that would be unethical because nobody should have that kind of power over other people. There's no basis for it. Genetic engineering on the other hand, you could just modify embryos so they're free from defects, more intelligent, better looking, etc. Hitler's Jewish holocaust stuff was eugenics, elimination of 'bad' instead of encouragement of 'good'. I'm worried that if someone thinks the latter is ok, they will make the assumption the former is also acceptable. Therefore, since one is unacceptable, neither can be.
If we go along the path eugenics, its not long before we decide on some standardized genetic build and replicate it to the point where uniqueness dies. Because dumb parents occasionally have smart kids too. Our species would be better off if the dumbest poorest laziest motherfuckers didnt have the most children.
The way mutations work, it could be that some neutral or livable-but-unfavourable trait combines with some other trait to result in something better down the line. Its based on false assumptions and psudeo-science and has an equal posibility to remove potential as it does to refine it as its the western equivilent of voodoo.
Stopping people from having the free will to breed with whomever they want is unethical. What are ethics? Ethics isn't something that's just written in stone; you have to justify why you think so. Ethics are a man made idea. If human race end up with a monoculture one disease could wipe us out. All it would take is the right flu and goodbye human race. We need to keep some mutts around for genetic diversity.
