Scientists are trying to use CRISPR to fix everything. What’s wrong with that?

An exploration of the ethics around CRISPR’s gene-snipping technology yields new insights on how to harness biotechnology that’s powerful enough to alter humanity.

In the world of biology — and coming soon to the wider world — enthusiasm and optimism continue to spread about CRISPR, a technology that allows precise editing of DNA.

If you’re a scientist who works with genes, it has already rocked your world: You can now snip an unwanted gene out of a DNA strand and replace it with another. Unlike the expensive blitz approaches of previously developed gene therapies, CRISPR techniques allow scientists to zero in on and knock out one problematic sequence. A process that used to be difficult, slow and haphazard has become a whole lot easier, faster and cheaper, opening up applications from medicine to agriculture. As journalist Carl Zimmer says: “Nobody’s found any place where it doesn’t work.”

CRISPR, an acronym for the unwieldy phrase “Clustered Regularly Interspaced Short Palindromic Repeats,” is now being tested with mosquitos to counter malaria and Zika; used to engineer disease-resistant livestock; and targeted to remove things like HIV and cystic fibrosis from human DNA. But more controversially, CRISPR has...