The main objection to He’s supposed gene-editing of Nana and Lulu boils down to one simple fact: messing with a human’s genes is incredibly dangerous and inhumane, mostly because we don’t fully understand how it works. He claims to have used the gene editing tool CRISPR to remove Nana and Lulu’s CCR5 gene, which should make them immune to HIV, but the genetic ripple effect on these children may go much deeper. According to Mazhar Adli, a researcher at the University of Virginia School of Medicine: “Deleting a single gene may not only alter how other genes are going to function but also may alter the overall behavior of the cell and the phenotype of [the] organism.”
Because of the complex interactions of genes and cells, removing one gene can have unforeseen consequences that can range from benign to devastating. The CCR5 gene, for example, affects the functioning of white blood cells and a person’s vulnerability to the West Nile virus. In time, gene editing may lead to a phenomenon called mosaicism, in which a person’s cells (which usually have uniform genetic make-ups) become a mixture of altered and unaltered genes, which can lead to disease in itself.
Putting aside Stephen Hawking’s fears of a new race of genetically altered superhumans and GATTACA‘s vision of a new generation of designer children, He’s genetically altered babies could end up being debilitated by his meddling (that is, if he’s telling the truth).