Can genetic technology give you the perfect baby? The revelation last October that a firm called Heliospect Genomics is planning to make that promise to parents, by genetically screening IVF embryos to identify the “best”, has reignited the debate over the ethics and scientific viability of the claims.
Heliospect is being evasive about its plans, which were brought to light by an undercover operation by the campaign group Hope Not Hate. Investigators for the group say they were told by company representatives that genetic screening of embryos could offer an average gain in IQ of up to six percentage points and that the screening could be conducted on up to 100 embryos.
Making this many embryos by conventional IVF would be very challenging, but it is possible that one day an almost unlimited supply of human eggs might be grown from stem cells in the lab rather than having to be extracted from ovaries – a process that has already been conducted for mice.
This is not the first time embryo screening for IQ has been mooted. It is illegal in the UK, but IVF is regulated much more loosely in the US, and a New Jersey-based company called Genomic Prediction said in 2018 that it would offer to screen embryos for low IQ, only to later withdraw the plan because of controversy.
The concept is based on the well-established fact that intelligence – as measured by IQ, which is controversial in itself, but also using actual educational achievement as a proxy – has a degree of heritability. Estimates vary widely, and seem to be dependent on socioeconomic circumstances, but it seems likely that around 50% of intelligence is acquired via genes.
One can quibble about the figures, but the heritability of IQ is not surprising: some correlation with genetics can be found for just about any trait, from height to schizophrenia.
But this does not mean there are intelligence genes. Some (typically rare) inheritable diseases, such as cystic fibrosis, can be traced to variant forms of a single gene. But studies seeking the genes that affect complex traits like intelligence show these to be polygenic: the differences between individuals may be correlated with differences in many genes, each of which has only a tiny influence and many of which have complicated and hard-to-define roles in the development and maintenance of the body.
That has not deterred some health companies from making predictions about such complex traits based on genetics. They use algorithms to predict the likely ranking of an individual – or an embryo that might be grown into one – based on their personal profile of many gene variants.
But therein lies the fundamental limitation of any attempt to screen embryos this way: it is merely probabilistic. A prediction might claim, for example, that a child would have a 40% chance of being within the top 20% of the IQ distribution for a population. That’s as good as it can get.
What’s more, because many genes may influence more than one trait, by selecting an embryo for IQ, parents would not know what else they might be selecting for. Underlying all this is a simple truth: the only way one can really know what an embryo will turn out like is to grow it into a baby.
Companies offering polygenic embryo screening don’t seem eager to acknowledge or explain such nuances. Heliospect’s CEO, Michael Christensen, is reported as saying, “Everyone can have all the children they want and they can have children that are basically disease-free, smart, healthy.” The idea that somehow the “right” genes can protect against all disease would be laughable, were it not coming from a company that seems intent on persuading parents it is possible.
These ideas are not just reminiscent of eugenics; they are literally and precisely that, the word meaning “good genes” – or in the original ancient Greek, well-born. Some seem intent on rescuing the term from its disreputable past: an adviser for Heliospect has painted “liberal eugenics” as simply a desirable empowerment of parents to “improve their children’s prospects”.
Genetics experts have a duty to debunk the false promises. Some are rising to the challenge. Last March, Simon Fisher, an expert on the genetics of cognition, and his colleagues illustrated the pitfalls of polygenic screening by applying it to DNA analysis of Beethoven’s hair. They showed that the great composer’s genetic profile predicted that his ability to synchronise to a beat – an attribute considered important for musicality – would be rather poor.
Parents seeking a musically gifted child would probably have been encouraged to throw away the embryonic Beethoven. Any parent lured by the promises of the likes of Heliospect should consider that.
