On Wednesday, a panel of bioethicists and scientists granted tentative approval to a form of genetic engineering that could result in babies with genetic material from three parents. The purpose of the process, known as mitochondrial replacement techniques (MRT), would be to prevent congenital disease.
MRT could correct serious congenital diseases that are passed down from the mother through genetic material found in the mitochondria, small organs in a cell that are often described as the cell’s power plants. Mitochondrial DNA is found only in eggs, not in sperm, and is therefore only passed from mother to child, which is why the committee is recommending limiting the procedures to only male embryos.
The panel stated that MRT should be used rarely and with extreme caution and “abundant government oversight.” The guideline of “males only” is intended to prevent introducing unwanted and irreversible genetic changes to the human species. R. Alta Charo, University of Wisconsin professor of law and bioethics, said “if there are adverse events, they would not be reverberating down the generations.”
The committee convened last year at the request of the U.S. Food and Drug Administration. They concluded that it is permissible ethically to “go forward, but with caution.” However, panel members noted that someone with genetic material from two mothers could potentially have to deal with questions of identity and ancestry.
Mark Sauer, professor of obstetrics and gynecology at Columbia University and a member of one of the panels, called the report “more of a yellow light than a green light.” However, he said he thinks “it’s a great step in the right direction.”
The committee also considered the danger of people trying to use the new technique to create designer babies that are physically or intellectually superior. Critics also say that the number of women who could be helped by the experiments is so small as to not be worth crossing a line that has long been considered off-limits.
Mitochondrial disorders range from mild to severe, and there is often no treatment. The affected child typically dies early in life after suffering debilitating and progressive symptoms. MRT would allow scientists to create eggs free of mitochondrial defects through removal of the defective mitochondrial DNA. They would then replace it with healthy DNA from another woman’s eggs, thus leaving a child with DNA from three parents.
Despite caution and reservations, the committee says the potential benefits make the research worth pursuing, although with careful oversight.