Kenan Malik in Pandaemonium:
The British Parliament can be an archaic, backward-looking institution, wedded to tradition, and not known for taking a revolutionary stance. Yet its members have just made a groundbreaking decision, one that no other legislature has so far been willing to contemplate. They approved legislation that makes Britain the first country formally to allow the creation of what many call ‘three-parent babies’. Supporters say the procedure will enable women to avoid passing on certain severe and even deadly genetically inherited diseases. But many regard the new law as an unwise, even immoral, move — the first step toward the creation of ‘designer babies’. Some even see it as a new experiment in eugenics.
‘Three-parent babies’ is a sensationalized term to describe a special form of in vitro fertilization, or IVF, that is better labeled ‘mitochondrial transfer’ or ‘mitochondrial donation’. Every human cell comprises two main parts: the nucleus and the cytoplasm. The nucleus contains the DNA, the genetic code that helps shape inherited traits. The cytoplasm is the workshop of the cell, where most day-to-day functions occur. Among its constituent parts are mitochondria, tiny organelles whose job it is to provide energy. Each mitochondrion contains tiny amounts of its own DNA, some 37 genes compared with the 20,000 or so in the nucleus. (It is thought that way back in evolutionary history, a free living bacterium became trapped in a host cell, where it boosted the cell’s capacity to produce energy; over time, it evolved into an organelle, an intimate part of the cell, but retained its own DNA.)
Mitochondrial DNA plays no part in determining an individual’s inherited traits, such as those that shape appearance or talents. But if it malfunctions, it can cause terrible conditions like muscle weakness, seizures, blindness, deafness, organ failure and even death.