A baby stiffly lays in a cardboard box, surrounded by package bubble wrap.

As of this year, the creation of genetically engineered and enhanced future human beings is no longer a scientific hypothetical. It is a social justice challenge.

Human germline modification - that is, altering the genes of gametes or early-stage embryos in order to manipulate the traits of future children and generations - raises hugely consequential safety, social, and ethical concerns. The risks range from irreversible health harms to the introduction of a new era of eugenics, with exacerbated or new forms of social inequality, discrimination, and conflict. For these reasons, human germline modification has been widely considered off-limits, and is formally prohibited in more than 40 countries.

Over the past several years, the development of "gene editing" techniques has triggered renewed debate about human germline modification because they provide a relatively more accurate way to attempt to engineer traits by altering DNA in the nuclei of cells. During the same time period, a different set of biological engineering techniques has also become highly controversial. These "mitochondrial manipulation" (or "three-person IVF") techniques involve removing and recombining components of cells - more...