What concerns exist about using genetic engineering to alter human traits such as appearance or cognition?

The use of genetic engineering to alter human traits such as appearance or cognition raises profound ethical and social concerns, particularly regarding the potential for "designer babies" and the morality of tampering with human development.31

Key concerns include:

• Unintended Consequences: Because the long-term effects of germline editing—changes that are heritable—remain incompletely understood, there is a significant risk that scientists might unintentionally introduce new genetic errors while attempting to modify others.21
• Ethical and Moral Implications: Critics argue that designing humans violates human dignity, as it implies individuals can be manufactured by others. This has sparked debates about the ethics of "tampering with nature" and the potential for abuse by authoritarian regimes.3451
• Equity and Access: There are ongoing questions regarding who would have access to such technologies, potentially exacerbating social inequalities.1
• Eugenics: These advancements have renewed concerns about a "new eugenics," where society might attempt to identify and eliminate "undesirable" traits or promote "genetically superior" characteristics, echoing historical eugenic ideologies.53

In response, many countries and international organizations have established guidelines or restrictions to govern human gene editing, emphasizing the need for safety and rigorous ethical consideration.21