World IVF Day 2025: What is Mitochondrial Therapy, the science of 3-parent babies?

Mitochondrial diseases are rare but they affect vital organs like the brain, heart, and muscles (Image: Pexels)

On World IVF Day, let’s look beyond conventional fertility treatments to a bold frontier in reproductive medicine. Sometimes called “3-parent IVF,” this scientific breakthrough may help families deal with inherited genetic disorders. While still under close scrutiny worldwide, MRT offers the chance to break cycles of illness and give future generations a stronger, healthier start, especially for women worried about passing on  life-limiting diseases.

A recent study in The New England Journal of Medicine reports on eight healthy infants born following mitochondrial replacement therapy (also known as mitochondrial donation or pronuclear transfer), in one of the largest clinical applications of its kind. Conducted at Newcastle University and authorised under the UK’s Human Fertilisation and Embryology Authority, the technique replaces a mother’s faulty mitochondria with healthy donor mitochondria while preserving her own nuclear DNA.

The infants, now aged between a few months and two years, show no signs of mitochondrial disease and are progressing normally. Researchers emphasise cautious optimism and the need for long-term follow‑up to monitor outcomes.

Also read | Understanding IVF: Debunk the common myths and misconceptions 

For couples dealing with the inherited mitochondrial diseases, the struggle to conceive without risking their child's health can feel insurmountable, says Dr Mannan Gupta, Chairman & HOD-Obstetrics & Gynaecology, Elantis Healthcare, New Delhi. “Mitochondrial diseases are rare but they affect vital organs like the brain, heart, and muscles. These diseases pass down through the mother’s mitochondrial DNA, which traditional IVF cannot block. Nevertheless,  with mitochondrial replacement therapy, doctors are now able to sidestep that faulty genetic inheritance,” he explains.

MRT works by replacing a mother’s defective mitochondrial DNA with that from a healthy donor egg, resulting in an embryo with DNA from three people: The mother, father, and mitochondrial donor. “This gives families a real shot at having healthy children, free from the fear of passing on inherited disorders. MRT has already delivered healthy babies in a handful of cases globally,” the expert says.

Dr Gupta shares 5 important facts you should know about 3-parent IVF

• Targets only mitochondrial DNA: Unlike genetic engineering, MRT doesn’t alter traits like eye colour. It solely targets mitochondrial DNA, the ‘batteries’ of the cells.

• Gives hope to affected families: Families with a history of mitochondrial disease can finally consider genetically related children without high-risk outcomes.

• It is strictly regulated: It is only allowed under strict regulation in countries like the UK. In India, it remains under scientific and ethical review.

• Raises ethical questions: From questions about identity and consent to the long-term impact on future generations, ethical oversight is crucial.

• Not designer babies: “This is not cosmetic science. It’s a medical solution to a very real problem,” Dr Gupta clarifies.