When we think of designer babies, we may think of genome-edited babies with their DNA cut and spliced, perhaps using CRISPR. But in fact 'a less intrusive technology already exists, which does something similar.' That technology is genetic screening. The issue was recently considered in Babbage – The Economist's weekly Science and Technology podcast, which is available on SoundCloud. This podcast episode from 7 November leads with an eight minute segment entitled 'Designer Genes'. Senior editor Kenneth Cukier interviews science journalist Dr Ananyo Bhattacharya about gene screening human embryos, and the implications.
Gene screening is already used in humans to exclude embryos with heritable diseases such as cystic fibrosis in prenatal testing for IVF. Genomic Predictions, a US company, offers far more extensive screening of many genes, called polygenic scoring - and a couple from California are the first people going through its process right now. Instead of screening for a single disease-causing mutation, the company will screen around one million single nucleotide polymorphisms (SNPs) to build a bigger picture.
How does the technology work? 'SNP chips are essentially silicon chips with bits of DNA on them. When you run somebody's DNA over these chips the DNA sticks to it, and tells you whether the person has the particular SNPs in question,' said Dr Bhattacharya.
The chips are cheap – under US $50 each. It is a 'no-brainer' to apply them to screening disease genes such as those for breast cancer. But are they accurate? This depends on how much a disease has been studied - 'the more genetic information you have, the more reliable these tests are,' explains Dr Bhattacharya. He adds that, for heart disease, using algorithms and artificial intelligence, and information on multiple genes, 'you can predict quite reliably whether somebody will be at three or fourfold risk of developing a disease in later life.'
Although Genomic Predictions recently published their database analysis in Nature, there is still debate about how meaningful polygenic scores actually are (see BioNews 1025. The podcast briefly discusses how incomplete information can affect polygenic scoring accuracy (above), but does not address the crucial role that environmental factors also play in health. Indeed, the company website states that 'disease risk is not eliminated in embryos designated as 'normal risk'.
With a note of humour, Cukier suggests this is a fantastic technology that we should all embrace. 'Who could possibly be opposed to it?' he wonders. Well, as it turns out, when it comes to applying this to embryos – quite a lot of people. In the UK, Dr Bhattacharya says the Human Fertilisation and Embryology Authority (HFEA) would almost certainly not allow this technology, due to concerns it could be used to produce so-called designer babies, rather than for life-saving medical interventions. Most European countries would feel the same way. 'Even China would probably baulk at selecting embryos for their IQ,' he says. Why is this global first for human screening happening in America? Dr Bhattacharya says it has 'the laxest regulations, when it comes to reproductive technology, probably in the world'.
Indeed, much of the ethical issue comes down to what traits we should be allowed to select. 'Are we happy for people to select embryos on the basis of their intelligence? On whether they'll be good at playing cricket or football? Or whether they should have blonde hair and blue eyes?' asks Dr Bhattacharya.
Even if people were only trying to pick a healthy embryo, there are problems. 'A particular embryo may be at high risk of diabetes, but low risk of other diseases,' he adds.
Back to the USA, and Genomic Predictions. The company insists it won't screen genes associated with intelligence, doubtless to avoid controversy for the fledgling technology. But there is nothing to stop it doing so, either technologically nor legally. To phrase it another way – the company won't screen for intelligence genes. Yet.
'When we look back on this, we may see this as the start of designer babies, proper,' predicts Dr Bhattacharya.
This eight minute segment is highly informative (and the rest of the podcast is fascinating too, with discussions of cultural evolution and advanced building materials). The short time means that there is not enough time to discuss the topic fully – glaringly absent was any mention of last year's CRISPR-edited 'designer' babies by Dr He Jiankui (see BioNews 977, 988, 1001), or discussion of environmental influences and epigenetics on development. However, if you don't have access or time to read the full Economist article, this excellent science podcast is a fantastic resource.