Controversial Fertility Treatments Focus on Eggs’ Power Plants

Derived from bacteria, mitochondria are our cells’ energy-producing powerhouses. Now, a Massachusetts company is convinced that these microscopic cylinders are also key to conceiving a baby, and it has persuaded several groups of physicians outside the United States to test that controversial premise in women with fertility problems. More than 10 women are pregnant via the firm’s proprietary in vitro fertilization (IVF) method, which adds a bolus of a woman’s own mitochondria to her mature egg.

Meanwhile, the U.S. Food and Drug Administration (FDA) has erected roadblocks in front of a fertility specialist and a stem cell biologist who want to clinically test the mitochondrial hypothesis in the United States. The duo would like to harness a different IVF strategy: swapping out a woman’s mitochondria by transferring chromosomes from her egg into an egg from another woman. The technique, called mitochondrial replacement therapy (MRT), was just legalized in the United Kingdom to prevent rare genetic diseases. But even before that, the two researchers applied for permission to use it in women who are struggling to conceive...