Gene Editing for ‘Designer Babies’? Highly Unlikely, Scientists Say - The New York Times
Here is what science is highly unlikely to be able to do: genetically predestine a child’s Ivy League acceptance letter, front-load a kid with Stephen Colbert’s one-liners, or bake Beyonce’s vocal range into a baby.
That’s because none of those talents arise from a single gene mutation, or even from an easily identifiable number of genes. Most human traits are nowhere near that simple.
“Right now, we know nothing about genetic enhancement,” said Hank Greely, director of the Center for Law and the Biosciences at Stanford. “We’re never going to be able to say, honestly, ‘This embryo looks like a 1550 on the two-part SAT.’”
Even with an apparently straightforward physical characteristic like height, genetic manipulation would be a tall order. Some scientists estimate height is influenced by as many as 93,000 genetic variations. A recent study identified 697 of them.
Talents and traits aren’t the only thing that are genetically complex. So are most physical diseases and psychiatric disorders. The genetic message is not carried in a 140-character tweet — it resembles a shelf full of books with chapters, subsections and footnotes.
So embryonic editing is unlikely to prevent most medical problems.
But about 10,000 medical conditions are linked to specific mutations, including Huntington’s disease, cancers caused by BRCA genes, Tay-Sachs disease, cystic fibrosis, sickle cell anemia, and some cases of early-onset Alzheimer’s. Repairing the responsible mutations in theory could eradicate these diseases from the so-called germline, the genetic material passed from one generation to the next. No future family members would inherit them.
A composite image showing the development of embryos after injection of a gene-correcting enzyme and sperm from a donor with a genetic mutation known to cause hypertrophic cardiomyopathy. Credit Oregon Health & Science University
But testing editing approaches on each mutation will require scientists to find the right genetic signpost, often an RNA molecule, to guide the gene-snipping tool.