Gene editing has far more promise than peril

Modifying human DNA in ways that could be passed on to future generations has long been deemed ethically out of bounds. It's even illegal in a number of countries, including Canada.

But a new report, Human Genome Editing: Science, Ethics and Governance, prepared by the influential U.S. National Academy of Science and National Academy of Medicine, opens the door a crack to that possibility.

That is a distinct shift from the position of a blue-ribbon panel that, in late 2015, deemed so-called germ-line editing to be "irresponsible" because there are too many unknowns and a lack of public consensus.

The panel of eminent scientists at the NAS/NAM takes a more pragmatic view, saying essentially that editing of embryos is occurring now, so parameters should be established so that it happens responsibly.

The new report says inheritable genome editing should be allowed when it is the "last reasonable option" for parents. A theoretical example of this would be two potential parents who carry the cystic fibrosis gene, and that mutation being edited out of the embryo of their offspring.

Before resorting to "germ-line editing," the NAS/NAM panel adds, other existing options should be employed, such as selection of healthy embryos for in-vitro fertilization, and prenatal testing and aborting fetuses. They also stressed that genetic modification should be allowed only to prevent severe inherited conditions, not for purposes of "enhancement," such as greater height or more intelligence.

The nightmare scenario – played out in books such as Brave New World and movies such as Gattaca – is frightening. Some believe the new recommendations set us on the slippery slope toward that sort of genetic determinism. But perspective is required.

Every time a new reproductive aid comes along – artificial insemination two centuries ago, IVF in the 1970s, mitochondrial transplantation (three-parent babies) a couple of years back, we react with horror.

The same is true of scientific advances. The cloning of Dolly the sheep (in 1996) had experts predicting the imminent cloning of babies and the end of reproduction as we know it. Similarly, the development of revolutionary gene-editing tools CRISPR/Cas9 has prompted dire warnings of designer babies.

Made-to-order superbabies are not as easy to brew up in a lab as Hollywood would have us believe. There are, for example, more than 700 genes that influence height, so we're not going to be churning out armies of giants – or NBA stars – any time soon.

The tried and true method of sperm-meets-egg in real people is still the most efficient, cost-effective and fun way of making babies. The occasional assist from the lab, which helps those who would not otherwise be parents, is a bonus.

The reality today is that gene editing has far more promise than peril.

Currently, there are trials under way to test the idea of taking immune cells from cancer patients and altering them to make them more powerful, potentially enhancing treatment. And imagine if we could edit away non-inheritable traits such as HIV infection or blood disorders such as hemophilia. (Chinese scientists have already edited the DNA of embryos to remove the traits for another blood disorder, thalassemia, with mixed results.)

And, if we could use molecular scissors to snip out conditions such as cystic fibrosis or Tay-Sachs, would that be so bad? (Bearing in mind, of course, that there could be unintended consequences, so thorough research is required.)

All this to say that fear and revulsion are not a good basis for forging public policy.

Instead of banning practices such as germ-line editing (as Canada does in the terribly outdated Assisted Human Reproduction Act) we should be openly discussing the benefits and risks, and establishing ethical parameters.

That's what the NAS/NAM panel has done in its new report. If its recommendations seem vague, it's because they need to be. The science is evolving at breakneck speed. So are public expectations. It would be imprudent to draw a line in the sand when the sands are constantly shifting.