They are meeting in China; they are meeting in the United Kingdom; and they met in the United States last week. Around the world, scientists are gathering to discuss the promise and perils of editing the genome of a human embryo. Should it be allowed — and if so, under what circumstances?
The meetings have been prompted by an explosion of interest in the powerful technology known as CRISPR/Cas9, which has brought unprecedented ease and precision to genetic engineering. This tool, and others like it, could be used to manipulate the DNA of embryos in a dish to learn about the earliest stages of human development. In theory, genome editing could also be used to 'fix' the mutations responsible for heritable human diseases. If done in embryos, this could prevent such diseases from being passed on.
The prospects have prompted widespread concern and discussion among scientists, ethicists and patients. Fears loom that if genome editing becomes acceptable in the clinic to stave off disease, it will inevitably come to be used to introduce, enhance or eliminate traits for non-medical reasons. Ethicists are concerned that unequal access to such technologies could lead to genetic classism. And targeted changes to a person's genome would be passed on for generations, through the germ line (sperm and eggs), fuelling fears that embryo editing could have lasting, unintended consequences.