FDA weighs risks of 3-person embryo fertilization
Washington • Federal health regulators will consider this week whether to green light a provocative new fertilization technique that could eventually create babies from the DNA of three people, with the goal of preventing mothers from passing on debilitating genetic diseases to their children.
The Food and Drug Administration has framed its two-day meeting as a "scientific, technologic and clinical" discussion about how to test the approach in humans. But the technique itself raises a number of ethical questions, including whether the government should sanction the creation of genetically modified humans.
The FDA panel will hear from several prominent critics who oppose any human testing of the approach, arguing that it could be a slippery slope toward "designer babies," in which parents customize traits like eye color, height and intelligence.
But the field's leading U.S. researcher will be on hand to explain and defend his work, which he describes as "gene correction," rather than "gene modification."
"We want to replace these mutated genes, which by nature have become pathogenic to humans," says Dr. Shoukhrat Mitalipov, who will present on Tuesday. "We're reversing them back to normal, so I don't understand why you would be opposing that."
The FDA meeting was prompted by Mitalipov's research at Oregon Health & Science University in Portland, where he and his staff have produced five healthy monkeys using the DNA-replacement technique. He is seeking FDA approval to begin testing in a handful of women who carry defective genes that can lead to devastating diseases in children, including blindness, organ failure and epilepsy.
An estimated 1 in 5,000 U.S. children inherit such conditions because of defective DNA in their mitochondria, small energy-producing organs found in the cell. Unlike most DNA located in the nucleus of the cell mitochondrial DNA is passed along only by the mother, not the father.
The experimental technique, if approved for use, would allow a woman to give birth to a baby who inherits her normal nucleus DNA but not her defective mitochondrial DNA.
To accomplish this, researchers would remove the nucleus DNA from a healthy female donor's eggs and replace it with the nucleus DNA of the prospective mother. After fertilization, the resulting child would inherit the mother's nucleus DNA which contains most inherited traits like eye color and height but the donor's healthy mitochondrial DNA.
The technique initially made headlines as a way to create babies with three parents, but scientists say that's an overstatement, since the child would have only trace bits of DNA from the donor.
No matter how it's described, the technique faces opposition from a broad spectrum of critics who say it presents serious medical, ethical and societal dilemmas.
Chief among these concerns is that the genetic changes created using the technique would be passed down to future generations, potentially spreading unintended health consequences throughout the population.
In a letter to the FDA, the Center for Genetics and Society points out that more than 40 countries including Germany and France have laws banning human gene modification that is passed on to future offspring.
The group's director says mitochondrial replacement would help only a tiny fraction of patients affected by such disorders, and they have other options like egg donation to create healthy children.
"It does initially look like something you would want to support," said Marcy Darnovsky. "But the safety concerns and the social and ethical concerns are really overriding."
Still, many experts expect the FDA to eventually sign off on testing the technique. They note that regulators in the U.K. found broad public support for the research there, with no evidence that it would endanger mothers or their children. The U.K. has significantly more regulations surrounding in vitro fertilization than the U.S., where fertilization clinics are essentially a self-regulated industry.
And before the FDA considers the philosophical implications of genetically modified children, its first concern is the safety of any patients enrolled in experiments. In documents posted ahead of this week's meeting, the agency said it will seek public input on how to monitor the safety of women who undergo the fertilization process. The agency also wants to hear proposals for long-term follow-up of any children produced via the process.
Stanford University Professor Hank Greely says the FDA is taking the right approach by focusing on the immediate safety concerns, rather than speculating on whether this could lead to a "Brave New World" scenario of biologically engineered humans.
"We constantly live on slippery slopes and it's our job as moral humans to hold a good position on the slope," said Greely, a law professor who studies medical ethics. "If you're worried about genetically engineered monsters or superheroes then you try to stop that, you don't try to stop medically useful interventions because you're worried that 17 steps down the line it will turn into something we don't like."