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In 2015, the United Kingdom became the first country to pass legislation allowing the use of mitochondrial donation technology, pronuclear transfer. The technique is designed to limit, through in vitro fertilization, the transmission of mitochondrial DNA diseases in babies born to women who are at high risk, and for which there is no cure. Two studies published in the New England Journal of Medicine (NEJM) describe the results of the first treatments performed to date, from which eight babies have been born by mitochondrial donation, with reduced risk of disease.

A team from the Netherlands has successfully edited pathogenic mutations in mitochondrial DNA in human cells, changes in DNA that cause disease, according to research published in PLoS Biology. The authors used a genetic tool known as a base editor. Until now, techniques derived from CRISPR have made it possible to correct mutations in nuclear DNA, and new techniques are being developed that allow mitochondrial DNA to be edited.

A team from the Children's Hospital of Philadelphia and Penn Medicine (United States) has successfully treated a baby diagnosed with a rare genetic disorder using personalised CRISPR gene editing therapy. The baby, known only by the initials KJ, was born with a rare metabolic disease known as severe carbamoyl phosphate synthetase 1 (CPS1) deficiency. After spending the first months of his life in hospital on a very restrictive diet, KJ received the first dose of his tailored therapy in February 2025, between six and seven months of age. The treatment, which is being used for the first time for this type of disorder, was administered safely, and the baby is now growing well and improving. The case is detailed in a study published by The New England Journal of Medicine (NEJM).

A team of researchers has used embryonic stem cell engineering to create a bipaternal mouse - a mouse with two male parents - that lived to adulthood. Their results, published in the journal Cell Stem Cell, show how targeting a particular set of genes involved in reproduction enabled this breakthrough in unisexual reproduction in mammals.

The seventh Annual Report of the COSCE Transparency Agreement, prepared by the European Animal Research Association, which analyses transparency in the use of animals for scientific experimentation in Spain in 2023, was presented today. According to the document, transparency is consolidated among the signatory institutions -168 in 2024- and all of them publish a statement on their websites on the use of animals. Public mention of the number and species used stands at 47%, compared to 38% the previous year.