-Traits or Diseases?- Some people worry that eugenics will be used to create desirable humans just as often as it is used to treat diseases. Using eugenics to call for certain traits can have poor effects.
ex. Criminality- can prevent self defense
Unethical- Many opposers of eugenics believe that the Holocaust is a blantant representation of poor usage of eugenics. They even point fingers at the Christians, who helped abolish slavery but then killed thousands of nonbelievers.
Diversity Reduction- Many argue that by eliminating undesirable traits, it would lessen the gene diversity and therefore cause the body to lack other essential genes. The body could then become vulnerable to a disease because of its lack of genes.
Embryo Usage- The most debated aspect of eugenics. People disagree with tainting an embryo that has the potential for life.
Favoritism- What type of person constitutes one "unfit" for the world?
Heterozygous Recessive Traits- It is impossible to completely conceal heterozygous recessive traits. In modern day, only dominant alleles can be terminated. Since few diseases are dominant, like Huntington's disease, some suggest that eugenics serves a very small purpose because it can not rid gene pools of many diseases.