Can CRISPR Deliver Designer Babies?

Excitement about new game-changing gene editing technology, known formally as CRISPR/Cas9,  has spilled over from the dry pages of scientific journals into the wider world – and with good reason.

These tools act as precision molecular scissors for DNA, guided to almost anywhere in the genome according to the whims of the researcher wielding them. Once snipped, the resulting gap can be filled with any other stretch of genetic material, repairing, removing or even entirely replacing what was there before.

CRISPR is the research tool that biologists have dreamed of for decades: a quick, cheap and accurate way of hacking the genome of any organism, revealing the functions of previously mysterious genes or their genetic ‘control switches’. And the capacity that it brings to precisely engineer regions of our own DNA is truly revolutionary.
For a start, there’s the not-too-distant possibility of using CRISPR to repair cells taken from a patient with a genetic condition, pumping them back into the body to take over from their damaged colleagues. Looking further ahead, the technique could lead to the end of diseases caused by single inherited gene faults, such as cystic fibrosis, by repairing damaged genes in eggs, sperm or early embryos. Whether this happens in the UK is for policy-makers and the public to decide – as they do with any new reproductive technology – although I’d bet good money that countries like China will go ahead and do it anyway.

But future scenarios of babies born with genomes perfectly tweaked to order are wide of the mark. As I explore in my new book, Herding Hemingway’s Cats, the idea that our genome is a strictly-followed blueprint is hopelessly simplistic.

Traits such as height, weight and intelligence are affected by hundreds, if not thousands of regions within our DNA, along with a hefty dose of influence from the environment. Even a seemingly simple characteristic like eye colour is under the control of many genes, shaded by subtle variations from person to person.
Misguided public hysteria about genetically modified organisms in agriculture has already led to beneficial farming techniques being dropped in countries that can ill-afford to do so.  So we shouldn’t let overblown claims of ‘playing God’ with designer babies distract us from the real possibilities of using genome editing technology to make a positive impact on human health.

Kat Arney is a London-based science writer and broadcaster. Her book Herding Hemingway’s Cats is out now, published by Bloomsbury Sigma.