The new treatment that was allowed by the British Parliament on Tuesday is known as "three-parent" in vitro fertilization (IVF) because the babies, born from genetically modified embryos, would have DNA from a mother, a father and from a female donor.

In Britain's House of Commons on Tuesday, health minister Jane Ellison started the debate on mitochondrial donation by urging support for this change. "This is a bold step to take, but it is a considered and informed step," she argued.

The "three-parent" in vitro fertilization is intended to prevent women who are carriers of a mitochondrial disease from passing it on to their baby. Mitochondria are the energy-producing structures outside of a cell's nucleus. Defects in mitochondria can result in degenerative diseases such as fatal heart problems, severe muscle weakness, blindness and mental retardation.

The new technique involves removing the nucleus DNA from the egg of a prospective mother and inserting it into a donor egg from which the nucleus DNA has been removed. The resulting embryo would have the nucleus DNA from its parents but the mitochondrial DNA from the female donor. Scientists said that the DNA from the donor egg amounted to less than one percent of the resulting baby's genes.

Before the vote on mitochondrial donation, the UK's Chief Medical Officer, Dr. Sally Davies, said the new treatment should be legalized "to give women who carry severe mitochondrial disease the opportunity to have children without passing on devastating genetic disorders."

However, critics argued that the new technique would cross a fundamental scientific boundary. David King, director of the secular watchdog group Human Genetics Alert, was worried that it would pave the way for "eugenic designer-babies." Last week, the Church of England voiced concern that there had not been enough scientific study or consultation of the technique.

das/rc (AP/Reuters)