The egg question: Should scientists alter DNA of human embryos?

“Designer babies” is a phrase with Orwellian overtones – test-tube children made to order courtesy of the wonders of modern genetics. It’s a dream to some, a nightmare to others. The reality, of course, is more complicated and subtle. At present we have no idea how to safely enhance the human genome of IVF embryos to improve things like intelligence or athletic ability – even if this were possible or desirable.

But the day may soon come when we have to consider whether genetic changes to the chromosomes of IVF embryos should be allowed for medical purposes, such as avoiding inherited disorders. Currently, this “germline gene therapy”, as it is known, is illegal in the UK.

However, the UK’s IVF legislation was changed in 2008 to allow the genetic manipulation of human embryos for research purposes, if it is done under licence. As we report today, scientists have now applied for the first research licence to use a powerful gene-editing technique known as Crispr/Cas9 to alter the DNA of the chromosome of human embryos. This is a momentous decision. For the first time in the UK, regulatory authorities will have to consider whether to allow the genetic engineering of human IVF embryos – albeit for research purposes only and not for implantation into the womb, which remains illegal.

The technique will help scientists understand the basic biology of early human development, and more specifically answer questions about how the placenta forms and how it can sometimes fail to attach to the uterus – a cause of repeated miscarriages in some women.

But this research will inevitably open the discussion on whether we should, at some point, allow scientists to genetically modify IVF embryos for eliminating inherited disorders or creating resistance to disease. This is not about designer babies; it is an exciting new horizon for medicine.