U.K. Parliament Approves Controversial Three-Parent Mitochondrial Gene Therapy

The United Kingdom’s House of Commons voted overwhelmingly today to allow British researchers to pursue a new fertility treatment that could prevent certain kinds of genetic diseases. The technique, called mitochondrial DNA replacement therapy, could allow women who carry disease-causing mutations in their mitochondrial genes to give birth to genetically related children free of mitochondrial disease.

The measure, which passed 382 to 128, has been controversial, especially because it would alter the DNA of an embryo in a way that could be passed on to future generations. Some scientists and nongovernmental organizations have argued that not enough is known about possible side effects of the technique to go forward in human patients. “We believe the House of Commons has made a serious mistake, which we hope does not have dire consequences,” said Marcy Darnovsky, executive director of the Center for Genetics and Society in Berkeley, California, in a statement.

Proponents of the measure quickly began to celebrate. “I am delighted that [members of Parliament] have voted to allow the introduction of mitochondrial transfer techniques into the clinic,"...