Bonnie Steinbock, a philosophy professor at the University of Albany, says a major sticking point is the need for the procedure. Steinbock participated in a U.S. Federal Drug and Administration panel as an ethics expert in February 2014, during which doctors raised questions about mitochondrial transfer. They wondered: Why invest time and resources to study this treatment, or run the risk of bad outcomes, when you can just use a donor egg? The reason, she says, is that mothers with faulty mitochondria find it important to have a genetic connection to their kid. "They want the baby they would have had, but for their infertility," says Steinbock.