Credit: Kyle Bean

The term 'genetic engineering' has been around since the early 1970s, along with the idea that, by altering DNA, scientists can cure genetic disease or create superhumans. Reality, however, was much less exciting. It is only in the past few years that researchers have developed the tools that allow them to engineer the genome with the precision and ease originally envisioned — to be able to edit any DNA base anywhere in any genome (see page S2). A CRISPR–Cas9 plasmid, the most recent of the widely used genome-editing tools, now costs US$65 or less. It can be ordered online, arrives in the post and requires little specialist training to use.

It is this availability and simplicity that has allowed genome editing to become common practice. Agricultural scientists and infectious disease experts are doing it (see page S15), as are synthetic biologists (see page S14). Epigeneticists have modified DNA-editing tools to manipulate their objects of study (see page S12). Biotechnology companies are springing up, aiming to develop treatments based on genome editing. But some diseases are more amenable than others (see page S10). One of the most advanced therapies is one that shuts HIV out of immune cells (see page S8).

With so much activity, a thorough and inclusive discussion of the implications of this technology is vital. Which is why the foremost scientific societies of three countries — the United States, United Kingdom and China — have come together this December to sponsor an international summit on the topic of editing the human germ line. Now is the time for the most respected scientists in the field to lay out the risks and benefits of genome editing to society, as Jennifer Doudna and George Church do in this Outlook (see page S6 and S7).

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