First baby has been born using DNA from three parents in the embryo, AFP.
The contentious technique has been first used for a child brought to life five months ago in Mexico to Jordanian parents, said the report in New Scientist magazine described as an "exclusive."
The child is reported to be healthy and doing well.
Parents of a baby resorted to a technique to evade Leigh Syndrome, a fatal nervous system disorder carried by mother, who had passed on the genes to her two previous children who both died of the disease.
New Scientist concealed identities of parents and reported they sought the help of John Zhang, a doctor from the New Hope Fertility Center in New York City to have a baby that would be genetically related to them but would be deprived of the inherited disease.
The United States has not approved any three-parent method for fertility purposes, so Zhang went to Mexico where he was quoted by New Scientist as saying "there are no rules."
Justin St John, professor and Director of the Centre for Genetic Diseases at Monash University said: "As this technology is controversial and a world first, I think the investigators should have submitted a manuscript for full peer review instead of announcing these outcomes in this manner."
"Some of the babies went on to develop genetic disorders, and the technique was banned," said the New Scientist report.
"The problem may have arisen from the babies having mitochondria from two sources," report stated.
For now, Zhang and his team said the boy's mitochondria has been tested and "they found that less than 1 percent carry the mutation," said the report.
"Hopefully, this is too low to cause any problems; generally it is thought to take around 18 per cent of mitochondria to be affected before problems start."