




But what exactly does that mean? The work of Plomin and others has shown over the past few years that correlations exist between the code in our genomes and pretty much any trait you can think of, including IQ and academic achievement. Such links to complex traits (as opposed to single-gene diseases) are usually invisible for any individual gene, but become significant when the influence of hundreds or even thousands of genes are summed in “polygenic scores”.



What’s more, the many genes involved in a polygenic score for intelligence are in no sense “genes for intelligence”; they will have many roles. If you’re “selecting for intelligence” you don’t know what else you might be selecting for, for better or worse.

So the science behind embryo IQ testing is still shaky. But before we get too indignant about the horrors of designer babies, bear in mind that already we permit, even in the UK, prenatal screening for Down’s syndrome, a disability that produces low to moderate intellectual disability. It’s not easy to make a moral or philosophical case that the screening offered by Genomic Prediction for low IQ is any different. There may be more uncertainty but, given not all IVF embryos will be implanted anyway, can we object to tipping the scales? And how can we condone efforts to improve your child’s intelligence after birth but not before?

The questions are complicated. How to balance individual rights against what is good for society as a whole? When does avoidance of disease and disability shade into enhancement? Should society be more receptive to disability rather than seeing it as something to be eradicated? When does choice become tyranny?

In the UK we are extraordinarily lucky to have the HFEA, which frames binding regulation after careful deliberation and acts as a brake so the technology does not outrun the debate. “Embryo selection needs robust regulation that society can be confident in,” says Ewan Birney, director of the European Bioinformatics Institute in Cambridge. Leaving a matter such as this to unregulated market forces is dangerous.

Philip Ball is a science writer