Make me one with wings

Designer babies have long been the stuff of science fiction or scaremongering thought experiments. Now we really are on the cusp of making them possible, thanks to the new science of gene editing. But what is wrong with designer babies anyway?

Jennifer Doudna is one of the architects of the miraculous new biological technique that goes under the name CRISPR/Cas9, or CRISPR for short. It stands for “clustered regularly interspaced short palindromic repeats”, and was discovered in the DNA of bacteria as part of their weapons system for fighting off viruses. It turns out that this machinery can be co-opted and programmed by human beings. With this tool, you can cut and splice strands of DNA very precisely in any organism at all – including humans.

The book explains the science clearly and excitingly, as a kind of globalist detective story involving many teams across the world. Previous techniques for messing with the genome were either hit-and-miss or prohibitively expensive. But CRISPR is very cheap and easy to use, to the extent that there is literally an app for it: off-the-shelf computer software for deleting or adding instructions to the target DNA. CRISPR is basically a wordprocessor for the code of life.

This is tremendous news for people suffering from certain genetic diseases which can now, in principle, literally be edited out of their bodies. Already a young girl has been cured of leukaemia using carefully edited immune cells. Gene editing can also be targeted in other ways that would make a huge difference to public health: for example, to change the DNA of mosquitoes so they no longer carry malaria and other diseases, and to make food crops more disease-resistant, in a more efficient and less Frankenstein-y way than previous genetically modified organism (GMO) techniques could, since they relied on splicing in genes from other species. CRISPR could also be used to add to the gaiety of nations by, for example, resurrecting the woolly mammoth from preserved DNA fragments – or even, Doudna points out in a deadpan way, making unicorns and dragons.

Doudna (writing with her co-researcher, Samuel Sternberg) is very good at illuminating the science she feels justified pride in having helped bring about. A different editor might have advised her not to begin the book by relating a dream. (“Tell a dream, lose a reader,” said Henry James, a risk that applies equally to non-fiction.) On a few occasions, she seems slightly testy when describing rival papers appearing around the same time as her own, and she writes disapprovingly of how CRISPR is already subject to patent disputes – which is a bit rich considering she herself co-founded several companies in order to “commercialize”, or “monetize”, the technology. But overall her book is helped along by her evident joy in discovery.

The ethics of using CRISPR to treat sick people seem uncomplicated. More tricky is the argument about editing human embryos. This can remove the possibility of their turning out to have horrible diseases. So why not? The problem, as some see it, is that now you are editing the human “germline” – these edits will be passed on to the children of those children, and so on. You’re messing with the gene-pool of the species, rather than just fixing an individual.

Generalised worries about “eugenics”, Doudna points out, ignore the fact that we already make eugenic choices, in the case for example of pre-implantation genetic screening in IVF, choosing which embryo to use based on its predicted susceptibility to serious disease – and even when mothers take prenatal vitamins.

Humans, indeed, have been breeding themselves in haphazard and irrational fashion for hundreds of thousands of years, so who is to say a little forethought wouldn’t be a good thing? The unfairly vilified “father of eugenics”, the 19thcentury polymath Francis Galton, made the same argument: what evolution had done hitherto with immeasurable pain and waste, he argued, humans could now do with “intelligence and mercy”; indeed he thought it was our “religious duty” to do so. Galton never recommended exterminatory eugenics of the kind that sullied the 20th century, but even so Doudna may well have thought that to include him in this book would be a provocation too far.

Some modern philosophers, nonetheless, say that it would be outright unethical not to improve the human species in any way we can. Increasing our intelligence

Gene editing is about to make designer babies possible. Steven Poole reports You are messing with the gene pool of the species, not just fixing a person