The world's first human baby created from the DNA of three people has been born. An unidentified couple from Jordan used donated mitochondrial DNA from another woman to create a baby. They had previously lost two pregnancies due to Leigh syndrome, a devastating disease that affects the mitochondria of cells.
Scientists don't care much for the term 3-parent baby because it does not describe the procedure well. In the technique, used when mitochondrial DNA is impaired in the mother, a donated egg, complete with donated mitochondrial DNA, is used to house the mother's nuclear DNA. That modified egg is then fertilized with the father's sperm before it is then implanted back into the mother. Understanding that means knowing that very little donated DNA is going into the creation of that healthy embryo.
Most countries prohibit the alteration of reproductive cells and do not allow any type of human cloning. For this reason, it's not allowed in many places. Mexico is one of the countries where there are no laws regarding its use, so the procedure was performed there. Britain, after much debate, has decided to allow this technology as of last year.