Do Not Open the Door

Should CRISPR be used to alter the genes and traits of future children and generations? Dozens of nations have considered this prospect and decided that manipulating the human germline should be legally off limits. The U.S. and China have not.

Some gene-editing enthusiasts now want to reopen the question. The answer will affect us all and shape the future. Yet despite the stakes being so high, many discussions of heritable genome editing are distorted by dubious assumptions. The claim that editing human embryos is needed to save babies from inherited disease and could “reduce human suffering in profound and meaningful ways,” for example, is misleading for several reasons.

First is the substantial risk of introducing rather than preventing harm. Editing an embryo’s genes can go wrong in multiple ways, including off-target edits, on-target but inaccurate edits, and a condition called mosaicism that produces a mix of altered and unaltered cells in an embryo – and in the resulting child. No one knows what the health effects of these unintended changes might be, for that child or for future generations.

Second: Safe options...