Innovative Three-Parent Technique Yields Eight Healthy Babies in UK

LONDON — In a groundbreaking development in reproductive science, researchers announced the birth of eight healthy babies in the United Kingdom, utilizing an experimental technique that incorporates DNA from three individuals. This innovative approach aims to help mothers avoid the transmission of rare genetic diseases to their offspring. The findings were reported on July 17, 2025, during a presentation by experts from Newcastle University and Monash University in Australia at the New England Journal of Medicine.

The process, known as mitochondrial replacement therapy (MRT), seeks to prevent the inheritance of harmful mitochondrial mutations that can lead to severe health issues such as muscle weakness, seizures, and developmental delays. These mutations, which reside outside the nucleus of the cell, can be difficult to identify during conventional in vitro fertilization (IVF) processes.

Traditionally, DNA is inherited from both parents, but MRT introduces healthy mitochondria from a donor egg into the embryo, which retains the nuclear DNA from the mother and father. This revolutionary method was made possible by a law change in the UK in 2016, enabling such procedures to be conducted legally. This technique is also permissible in Australia, but remains prohibited in various other countries, including the United States.

According to Dr. Zev Williams, Director of the Columbia University Fertility Center, the advancement marks a significant milestone in reproductive technology. “Expanding the range of reproductive options will empower more couples to pursue safe and healthy pregnancies,” he stated. The technique allows embryos to possess DNA from three individuals: the mother, the father, and the mitochondrial donor.

The recent study involved fertilized embryos from 22 patients, resulting in eight live births, while one mother remains pregnant. Notably, one of the eight babies exhibited slightly elevated levels of abnormal mitochondria, although experts, including Robin Lovell-Badge from the Francis Crick Institute, indicated that these levels are not currently concerning and warrant monitoring as the child grows.

Andy Greenfield, a reproductive health expert from the University of Oxford, referred to this achievement as “a triumph of scientific innovation.” He emphasized that the mitochondrial exchange method would only be applicable to a select group of women for whom traditional methods of avoiding genetic diseases have proven ineffective.

Critics, however, caution against the long-term implications of such genetic interventions. Dr. Williams noted, “Currently, pronuclear transfer is not permitted for clinical use in the U.S., largely due to regulatory restrictions on techniques that result in heritable changes to the embryo.” He remarked that the future of such technologies in the U.S. remains uncertain, contingent upon ongoing scientific and ethical discussions.

In the UK, couples seeking to conceive using this method must obtain approval from the country’s fertility regulator. As of July 2025, 35 patients have received authorization to proceed with the MRT technique.

The emotional implications of this technology are profound. Liz Curtis, whose daughter succumbed to a mitochondrial disease, expressed her support for the research, highlighting the hope it brings to families facing similar challenges. Curtis established the Lily Foundation to raise awareness about mitochondrial diseases and promote research, reflecting the personal impact of this scientific advancement.

As this field evolves, the ethical, medical, and regulatory frameworks surrounding mitochondrial replacement therapy will be scrutinized, particularly in countries like the U.S. where such practices are currently restricted. The landmark births in the UK may signify a pivotal moment for reproductive medicine, possibly opening doors for future innovations aimed at combating genetic diseases and improving the lives of countless families worldwide.