For the first time, a baby boy has been born using DNA from three people. The boy’s mother carries the Leigh Syndrome, a genetic disease caused by mutations in Mitochondrial Dna. Mitochondria are prokaryotes cells which have been ancestrally incorporated into the eukaryotic cells for energy production through the oxidative respiration; all cells, including egg cells, contain mitochondria and their genetic material. During fertilization, the mother contributes with her DNA and mitochondria and in this case, she was responsible for genetic transmission of Leigh syndrome to her child. To avoid passing on the disease-causing mitochondrial DNA, scientists at the New Hope Fertility Center in New York City removed the nucleus from one of the mother’s eggs and inserted it into a donor egg, which had its own nucleus removed. This egg was then fertilised with the father’s sperm. The resulting embryo therefore had nuclear DNA from its parents and mitochondrial DNA from the donor. There are many concerns, legal, ethical and medical, about the safety of this procedure which has not been approved yet by FDA. Some caution should be advice because few births and few data are currently available; however, up to date the 5-month-old boy is healthy.