In a groundbreaking first, eight healthy babies have been born following in vitro fertilization (IVF) that included genetic material from three parents.
This innovative technique aims to reduce the risk of transmitting life-threatening hereditary diseases originating from the mother’s genetic material. The babies were born in England as part of a medical trial that lasted several years, with results published this week in leading scientific journals.
The treatment focuses on replacing defective mitochondrial DNA in the mother. Mitochondrial DNA is a tiny genetic material located outside the cell nucleus, inside structures called mitochondria, which produce energy for the body.
Mitochondria are passed down only from the mother, so mutations in this genetic material can lead to severe diseases. Because mitochondrial DNA is separate from nuclear DNA (which determines most human traits), it can be replaced without affecting the child’s genetic identity.
The British trial, conducted at a fertility center in Newcastle, involved 22 women who met strict medical criteria, hoping to conceive without passing on harmful mutations. Eight of the women gave birth to healthy babies: four boys and four girls, with ages ranging today from under six months to more than two years.
Mitochondrial diseases, which this technique seeks to prevent, are rare but devastating. These diseases affect cellular energy, causing severe symptoms such as blindness, diabetes, muscle degeneration, and even early death. One in 5,000 births is affected by such diseases, and there is currently no cure.
Genetic tests performed after birth confirmed that the babies did not inherit harmful mutation levels that would have compromised their health. In six cases, defective mitochondrial DNA levels were reduced by 95-100%. In two other cases, the reduction was 77 to 88 percent, still below the dangerous threshold. One baby experienced a temporary heart rate issue, which was successfully treated.
Renewed increase of defective mitochondria despite trial success
Despite the success, researchers noted an unexpected phenomenon in three of the children, where a “reversal” was observed after birth—a renewed increase in the percentage of defective mitochondria in the cells. The implications of this phenomenon remain unclear, and the babies will continue to be monitored in the years to come.
The UK was the first country to approve the procedure in 2015, but the technique remains controversial. Many countries, including the United States and France, still prohibit the method. Concerns range from ethical issues related to the destruction of embryos during the procedure to fears that this technology could lead to the creation of "designer babies" with pre-selected traits.
Despite the criticism, public health and genetics experts view the trial as a major success, expanding fertility options for women at high risk of transmitting hereditary diseases. However, the procedure is currently approved only in cases where the risk of passing on a fatal disease is clear and proven.
The babies born in this trial are not the first to have DNA from three people. The first such case occurred in 2016 when a similar procedure was performed on a Jordanian woman treated by American doctors in Mexico, a country with no regulations on the matter.
Although the researchers emphasize that only about 0.1 percent of the babies' DNA comes from the donor, the genetic intervention raises significant medical, ethical, and social implications. In a world where medicine is advancing toward genetic design, this trial represents a milestone in the fight against hereditary diseases and life-saving advancements, but also raises serious questions about the boundaries of human intervention.