In the three months since He Jiankui announced the birth of twin girls with edited genomes, the questions facing the scientific community have grown knottier.
By engineering mutations into human embryos, which were then used to produce babies, He leapt capriciously into an era in which science could rewrite the gene pool of future generations by altering the human germ line. He also flouted established norms for safety and human protections along the way.
There is still no definitive evidence that the biophysicist actually succeeded in modifying the girls’ genes — or those of a third child expected to be born later this year. But the experiments have attracted so much attention that the incident could alter research for years to come.
Chinese authorities are still investigating He, and US universities are asking questions of some of the scientists he consulted. Meanwhile, calls for an international moratorium on related experiments, which could affect basic research, have motivated some scientists to bolster arguments in favour of genome editing.
Some are concerned about how the public scrutiny will affect the future of the field, whether or not researchers aim to alter the germ line. “The negative focus is, of course, not good,” says Fredrik Lanner, a stem-cell scientist at the Karolinska University Hospital in Stockholm, who has been editing genes in human embryos to study how cells regulate themselves.
But others predict that the He affair might propel human gene editing forwards. Jonathan Kimmelman, a bioethicist specializing in human trials of gene therapies at McGill University in Montreal, Canada, argues that definitive action in the wake of the scandal could expedite global cooperation on the science and its oversight. “That would stimulate, not hinder, meaningful advance in this area,” he says.