The process incorporates DNA from three people
The first baby has been born using a new "three person" fertility technique by US scientists.
New Scientist reports Abrahim Hassan is the first baby to be born using the technique that incorporates DNA from three parents.
The technique allows parents with rare genetic mutations to have healthy babies.
It has only been legally approved in the UK. British MPs voted to legalise the procedure in 2015.
New Scientist says the birth of Abrahim, whose Jordanian parents were treated by a US-based team in Mexico, "should fast-forward progress around the world".
It says the child's mother carries genes for Leigh syndrome - a fatal disorder that affects the nervous system.
The couple are said to have sought out the help of Dr John Zhang at the New Hope Fertility Center in New York.
The method approved in the UK is called pronuclear transfer - and involves fertilising both the mother’s egg and a donor egg with the father’s sperm.
Before the fertilised eggs start dividing into embryos, each nucleus is removed. The nucleus from the donor egg is discarded and replaced by that from the mother’s.
But as both parents are Muslim, this technique was not seen as appropriate - they were opposed to the destruction of two embryos.
So Dr Zhang took a different approach, called spindle nuclear transfer.
He removed the nucleus from one of the mother's eggs and inserted it into a donor egg that had had its own nucleus removed.
The resulting egg - with nuclear DNA from the mother and mitochondrial DNA from a donor - was then fertilised with the father's sperm.
As the procedure has not been approved in the US, this took place in Mexico.