LONDON (AP) — Britain’s fertility regulator confirmed Wednesday the births of Britain’s first babies created using an experimental technique that combines the DNA of three people, in an effort to prevent children from inheriting rare genetic diseases.

The Human Fertilization and Embryology Authority said fewer than five babies have been born this way in the UK, but did not provide further details to protect the identity of the families. The news was first reported by The Guardian newspaper.

In 2015, the UK became the first country to adopt legislation regulatory methods to help prevent women with defective mitochondria, the powerhouse in a cell, from passing defects to their babies. He The world’s first baby is born use of the technique was reported in the US in 2016.

Genetic defects can result in diseases such as muscular dystrophy, epilepsy, heart problems, and intellectual disabilities. Approximately one in 200 children in Great Britain is born with a mitochondrial disorder. To date, 32 patients have been cleared to receive such treatment.

For a woman with faulty mitochondria, scientists take genetic material from her egg or embryo, which is then transferred into a donor egg or embryo that still has healthy mitochondria but has had the rest of its key DNA removed.

The fertilized embryo is then transferred to the mother’s uterus. The genetic material of the donated egg comprises less than 1% of the child created from this technique.

«Mitochondrial donation treatment offers families with severe inherited mitochondrial diseases the chance to have a healthy child,» the UK’s fertility regulator said in a statement on Wednesday. The agency said it was still «early days» but expected the scientists involved, at Newcastle University, to publish details of the treatment soon.

Britain requires that all women undergoing the treatment receive approval from the Human Fertilization and Embryology Authority. The regulator says that to be eligible, families must have no other options available to avoid passing on genetic diseases.

Many critics oppose the artificial reproduction techniquesarguing that there are other ways that people can avoid passing diseases to their children, such as egg donation or screening tests, and that experimental methods have not yet been shown to be safe.

Others warn that modifying the genetic code in this way could be a slippery slope, eventually leading to designer babies for parents who want not only to avoid inherited diseases but to have taller, stronger, smarter or more handsome children.

Robin Lovell-Badge, a stem cell expert at the Francis Crick Institute, a biomedical research center in London, said monitoring the babies’ future development would be critical.

«It will be interesting to know how well the (mitochondrial donation) technique worked on a practical level, whether the babies are free of mitochondrial disease, and whether there is any risk of them developing problems later in life,» he said in a statement.

Scientists in Europe published research earlier this year that showed that, in some cases, the small number of abnormal mitochondria that are inevitably transferred from the mother’s egg to the donor’s egg can reproduce when the baby is in the womb, thereby ultimately it could lead to a genetic disease. .

Lovell-Badge said the reasons for such problems were not yet understood and researchers would need to develop methods to reduce the risk.

Previous research evaluating another technique to create babies from three people, including an egg donor, she found that years later the children were doing well into their teens, with no signs of unusual health problems and doing well in school.

Doctors in the United States were the first to announce the world’s first baby using the mitochondria donation technique, after the treatment was carried out in Mexico.