'Designer babies' may not be as smart or tall as parents expect, study warns

Gene-edited babies won’t get the boost that parents expect, academics have warned after a study showing limited benefits to height and intelligence.

The study prompted academics to dismiss specifically engineered babies as ‘the realm of science fiction.’

The study showed that although embryos could be profiled with traits such as height or IQ, they would only be expected to be around 2.5cm taller and 2.5 IQ points higher than average.

In addition, the researchers flagged that there were “multiple ethical and other factors” that limit how much we can impact what genetically edited babies will be.

The research, published in the academic journal, Cell, was conducted by running simulations of genomes of real people to create possible embryos when they were paired up.

Study author, Shai Carmi, of the Hebrew University of Jerusalem, said: "If someone selected an embryo that was predicted to have an IQ that was two points higher than the average, this is no guarantee it would actually result in that increase.

"There is a lot of variability that is not accounted for in the known gene variants."

The technique of screening IVF embryos to look for characteristics before they are implanted is known as preimplantation genetic screening (PGS).

It is currently used in reproductive medicine in order to identify defects in embryos and prevent the risk of passing on inherited disorders to unborn babies.

Currently the use of PGS is highly regulated in the UK and follows strict licencing conditions.

In November last year, the Chinese scientist, He Jiankui, claimed to have created the world’s first genetically edited babies, prompting widespread condemnation from the scientific community.

So-called ‘designer babies’ have been a topic of scientific and ethical debate for years since the technology of genome editing first started being explored.

Earlier this week a report by Dr Kevin Smith, a bioethicist from Abertay University suggested that the risks of genome editing are now so low that it is both “ethically justifiable” and “highly desirable” to start using the method on human embryos.

Dr Liz Ormondroyd, from the Radcliffe Department of Medicine, University of Oxford, said: “It has long been feared that genetic information might be used to select embryos based on desire for characteristics such as increased height or intelligence.

“This computer simulation study shows that, for these complex characteristics, ‘designer babies’ remain in the realm of science fiction.”