World of Wonders

Modified People

We can engineer human traits, but should we?

By Gaia Vince | July 29, 2015
Andy Leppard/Flickr
Andy Leppard/Flickr


We have entered the age of genetically modified people: scientists have successfully edited the genes of a human embryo, replacing a gene that causes disease with a healthy one.

The idea of a mutant race of humans looms large, making us understandably squeamish about manipulating embryos. The experiment, by Chinese researchers, was so ethically controversial that the two biggest science journals, Nature and Science, refused to publish it, even though it involved non-viable embryos, meaning that it was impossible for them to develop further than a bunch of cells before dying. A minor open-access journal eventually published the results, making them available without a subscription. And it sparked intense debate among scientists about whether such research should be allowed to continue.

We should all engage in this debate.

That experiment was only partially successful. The scientists managed to remove the gene in only one-third of the 86 embryos in which they attempted to do so, and the technique led to a worrying number of mutations and incorrect gene insertions. The machine the scientists used to replace the faulty gene was not the latest, state-of-the-art one; perhaps others would have more success and fewer side effects. Even so, we are far from ready, technically, to start using the technique on viable embryos.

But how ready are we to accept the ethical implications? There are plenty of diseases—some that are fatal in childhood—caused by a faulty gene. Many argue that editing an embryo to eliminate diseases, such as sickle cell, is an ethical imperative that justifies experimentation, even if that means creating mutant embryos in the lab, all of which would die within days. Others disagree.

This type of gene manipulation is still in its infancy, but our capabilities will improve rapidly. We have only to look at the vast diversity of life that has evolved on the planet to see where genetic tweaks could lead us. During our own brief time here (less than 200,000 years), we have been carrying out plenty of genetic manipulation, albeit at a slower pace. We have tamed the wolf, for example, to sit nicely in a poodle parlor and pacified the auroch into a living factory of milk, beef, and leather. As our technology improves, it may quickly lead us beyond the bounds of nature.

Because, while we have been populating the planet with our own genetically altered animals, wild ones keep disappearing. What if we could genetically tweak wolves to dislike the taste of sheep? Or make elephants that do not grow desirable tusks? Conversely, what if we could tweak humans not to desire elephant tusks? Or engineer people to live happy yet sustainable lives?

It’s time for us, maybe the last generation of unmodified humans, to have our say.

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