What if parents could customize a baby much like choosing a car, selecting attributes like eye color, size, and the ability to run fast?
It sounds like science fiction, but the reality might not be as far off as you think.
In November, He Jiankui, a researcher in China, upended the world of genetics by announcing the first gene-edited babies; he claimed to have altered a gene in the embryos of a pair of twin girls to make them resistant to H.I.V., the virus that causes AIDS.
His announcement has set off an intense debate among scientists, many of whom see gene editing as a potentially promising avenue for fighting disease but worry that the technology is outpacing considerations of the ethical questions involved in altering human DNA.
“Should such epic scientific misadventures proceed,” says Francis Collins, director of the National Institutes of Health in Bethesda, Maryland, “a technology with enormous promise for prevention and treatment of disease will be overshadowed by justifiable public outrage, fear, and disgust.”
Scientists have contemplated changing human genes ever since the structure of the DNA molecule was discovered in 1953 (see “Genetic Breakthroughs”). But the invention of a powerful gene-editing technique called Crispr in 2012 sparked a scientific revolution, allowing researchers to edit DNA with unprecedented ease and precision. It has already been used to change some animals’ DNA, including that of pigs (making them immune to a virus) and salmon (so they grow faster).