Eugenics is natural and approved worldwide. Eugenics is natural. We see it in selecting crops for food, and in animal husbandry where certain breeds are selected for specific jobs or abilities.
The idea that eugenics will destroy variety is incorrect. Dogs came from wolves. Wolves still exist, as do hundreds of different dog breeds. The same can be said for cats and plants.
Even now, we select the best possible mate we can. This is natural. Eugenics simply enhances those traits we find desirable. These traits can be altered over successive generations if needed. The only people who are afraid of eugenics, are those who are concerned their genes will not be passed on into posterity.