"What we're seeing is a fast slide down a very slippery slope toward designer babies," warned Marcy Darnovsky on NPR's Morning Edition today. She portentuously added, "We could see parents feeling eager to give their children traits like greater strength, needs less sleep. Some people are saying that, 'Yes, there are genes for IQ and we could have smarter babies.'"
What has alarmed Darnovsky, a left-wing bioconservative from the Center for Genetics and Society? The fact that specialists at the Nadiya fertility clinic in Ukraine have used pronuclear transfer to help some parents to give birth to healthy babies.
First, a bit of biology. Every human egg cell contains between 100,000 and 600,000 energy-producing mitochondria floating in the cytoplasm outside the cell nucleus. While the vast majority of the DNA that makes up our genomes resides inside the nuclei of our cells, each mitochondrion has its own small genome consisting of 37 genes. Mutated mitochondrial genes can can cause disease. It is estimated that mitochrondrial diseases are one of the most common groups of genetic diseases, with a minimum prevalence of greater than 1 in 5000 in adults.
Pronuclear transfer is used in cases where the mitochondria in a woman's eggs are mutated in some way that would produce disease in her children or cause her infertility. The procedure involves removing the two pronuclei, or unfused nuclei, of the egg and sperm from a day-old embryo and transfering them into an enucleated donor egg containing healthy mitochondria. Babies born via this technique thus have genes derived from three people: the nuclear genes from the mother and father, plus a comparatively tiny number of mitochondrial genes from the egg donor. Hence the sobriquet "three-parent babies."
Since mitochondrial DNA is inherited from a baby's mother, female children born using this technique will pass along the healthy donor mitochondria to their progeny. Bioconservatives like Darnovsky decry this as germ-line genetic engineering.
"It is pioneering work," the Columbia biologist Dietrich Egli said in the NPR story. Not exactly. The real pioneers were fertility specialist Jacques Cohen and his colleagues at St. Barnabas Hospital in New Jersey, who successfully used a similar technique back in 2001 to help women give birth to 17 babies. Instead of tranferring the pronuclei, as is done in Ukraine, Cohen transferred ooplasm containing mitochondria from healthy donor eggs to the eggs of women experiencing infertility. This prompted some similarly overwrought worries about designer babies, and the Food and Drug Administration (FDA) in 2001 essentially banned the procedure by asserting that ooplasm transfer was an "investigational new drug" requiring agency approval.
In 2016, the National Academy of Sciences issued a report endorsing the use of mitochondrial replacement therapies (MRT) in embryos to help parents have healthy babies. One catch: The report said it should only be used to produce boys, thus mitigating the possibility that the donor mitochondria would be passed along to future generations. But even that cannot proceed in the U.S. Since 2015, Congress has included provisions in its annual federal appropriations laws that prohibit the FDA from accepting applications for clinical research using MRT. Therefore, clinical research using MRT in human beings cannot legally proceed in the United States.
In light of this prohibition, American fertility specialist John Zhang in 2016 performed a successful pronuclear transfer in Mexico for a Jordanian woman burdened with the mitochondrial mutation associated with Leigh's Disease. The illness causes brain lesions, which killed her first two children. In August 2017, the FDA sent a letter to Zhang ordering his Darwin Life Company to cease marketing the MRT treatment on its website in the United States.
Now NPR is reporting that the Ukrainian scientists have formed a company, Darwin Life-Nadiya, with a New York clinic to market the service to U.S. women willing to travel to Ukraine. Ukrainian women will pay about $8,000 for the procedure; for foreigners, it'll be about $15,000. Hopefully the FDA will be more tolerant this time. So long as our Congress, our regulators, and the majority of our bioethicists continue to stand in their way, Americans suffering from the burdens of genetic disease and hoping to give birth to healthy children will be sadly forced to engage in this kind of reproductive medical tourism.
But what about Darnovsky's claim that MRT is the beginning of a fast slide down a very slippery slope toward designer babies? Bring it on. Parents using modern biotechnology to endow their children with longer, healthier, smarter, and perhaps even happier lives? It's hard to see any ethical problem with that.
For more background, see my lecture in Moscow on "Designer Babies and Human Enhancement":