But the technique—already approved in Great Britain—is controversial, and if it's approved, it would mean that those babies would carry genetic components from three different people for life.
Let's back up a bit: Mitochondrial disease involves a genetic mutation that can cause a number of health problems, including seizures, blindness, heart problems, and liver disease. About 4,000 people are born with the condition in the U.S. ever year. Because the disease is passed down from mother to child, many women with the condition decide to adopt rather than run the risk of having an affected baby. But now scientists think a type of gene therapy known as mitochondrial replacement could change all that.
To avoid passing on faulty DNA, scientists have suggested taking a donor egg from a woman with normal mitochondria, removing its nucleus, and replacing it with the healthy nucleus of an affected mother. Others think modifying a fertilized donor egg by transferring nuclear DNA from an affected mother might work. But critics say the social implications of having a child who technically has three parents are substantial. And the procedure, which has not yet been used to produce a person, may not be safe. Which is why the FDA asked the panel to review the technique and make a recommendation.
The panel said the technique should be used in clinical trials—but only on male embryos, since men don't pass down mitochondrial DNA to their children. They also suggested a number of steps to ensure the safety of the procedure, including keeping track of any children created with the procedure for years after they're born. If the technique works in male embryos, the panel said it could then be used to make female children as well.
"The limitation of use of mitochondrial replacement to males was a surprising and clever twist on their part that makes a lot of sense," Eli Adashi, a medical science professor at Brown University, told Genetic Expert News Service.
That said, if the FDA agrees with the panel, it would mean that the some of the fertilized embryos that are created won't be used simply because they're female—and "some may find [that] objectionable," Adashi said.
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