Dr. John Zhang, a U.S. fertility specialist at New Hope Fertility Center in New York, made history when he delivered the world’s first baby with three biological parents. Using a “three parent technique” that he originally proposed more than a decade ago, Dr. Zhang assisted a Jordanian couple give birth to a child with both parents’ DNA in the egg of a donor.
Under a “three-parent” technique, parents with rare genetic mutations can fertilize an egg while trying to remove any genetic mutation that may be carried by the father or mother. The parents approached Dr. Zhang after two of their other children died due to a rare disease known as Leigh syndrome, a fatal disease which gradually deteriorates the nervous system and results in respiratory failure, usually in the first few years of life. The couple also had four pregnancy losses. The baby’s mother carried recessive genes for the disease, although was not affected herself.
In order to avoid passing Leigh syndrome to another child, Dr. Zhang implanted the nucleus from the mother’s eggs into an egg of the donor which had its own nucleus removed. The egg was then fertilized with the father’s sperm and implanted in the mother who gave birth nine months later. The child was born in April 2016 but the couple and Dr. Zhang waited to announce the successful use of the “three parent technique” until now when they were also able to report that the baby did not develop Leigh syndrome.
Dr. Zhang’s procedure has not been without controversy. In fact, the procedure had to be conducted outside of the United States in Mexico in order to avoid United States regulations which have not approved the procedure. The procedure is approved in the United Kingdom, but in a slightly different manner than that utilized by Dr. Zhang. Notably, Dr. Zhang announced the “three-parent baby” technique 13 years ago but the medical paper on his findings was just published this year.
The medical community has reacted wildly both in approval and disapproval of the announcement, with the Center for Genetics and Society calling it “biologically extreme” and “troubling” while New Scientist has called it “revolutionary”.