tl;dr: Earlier this month, a study published in Nature by Shoukhrat Mitalipov, head of the Center for Embryonic Cell and Gene Therapy at the Oregon Health and S

tl;dr: Earlier this month, a study published in Nature by Shoukhrat Mitalipov, head of the Center for Embryonic Cell and Gene Therapy at the Oregon Health and Science University in Portland, suggested that in roughly 15 percent of cases, the mitochondrial replacement could fail and allow fatal defects to return, or even increase a child's vulnerability to new ailments. It's not a risk of editing the genes so much as a risk of the treatment failing.