England is on the verge of passing a new law that would involve making a new form of IVF (in vitro fertilization) available to couples. This new form of IVF would include DNA from three parents, and if passed, would be the first law to allow for pre-birth DNA modification.

The new procedure involves replacing mitochondrial DNA (mtDNA) to avoid destructive cell mutations. Mitochondria convert energy from food into what our cells need to function, and they carry their own DNA apart from the nuclear DNA in our chromosomes where most of our genetic information is stored. Only the mother passes on mtDNA to the child, and it can sometimes contain mutations that can lead to serious health problems or genetic defects. To put some numbers behind the science, an estimated 1 in five to ten thousand people carry mtDNA that contains mutations. These mutations can lead to such things as blindness, diabetes, dementia, epilepsy and several other impairments. 
 
By combining normal mtDA from a donor with the nucleus from a prospective mother’s egg, the newborn is theoretically free from mutations that would eventually lead to one or more of these disorders. While never tried in humans, researchers have successfully tested the procedure in rhesus monkeys.