A small number of fertility clinics around the world are offering a controversial treatment: furnishing clients' embryos with donated mitochondria to increase the chances of taking home a baby — despite the absence of rigorous clinical evidence, an investigation by Nature has found.
The method, called mitochondrial replacement therapy (MRT), involves removing the nucleus from a person's egg or a couple's single-cell embryo and transplanting it into an egg from a young donor. The theory — unproven in controlled trials — is that the donor's mitochondria help the egg or embryo mature. Any resulting baby would carry nuclear DNA from its biological parents and mitochondrial DNA from the donor.
MRT has a proven role in preventing the inheritance of mitochondrial diseases: last year, the first clinical trial for that purpose reported the birth of eight healthy babies. But Nature identified clinics in the Bahamas, the Philippines, Albania and Ukraine that advertise MRT to improve IVF success for clients without such mutations, sometimes calling it 'oocyte rejuvenation.' IVF Asia Group in the Philippines says a 40-year-old receiving MRT 'is now getting results similar to as if they were 25.'
Clinicians and scientists are alarmed. 'I'm pretty horrified,' said Richard Anderson, a fertility doctor at the University of Edinburgh, after reviewing one clinic's offering. Mary Herbert, a reproductive biologist at Monash University who has led an MRT trial, called marketing the treatment to desperate patients without published evidence 'fundamentally wrong.' Robin Lovell-Badge of the Francis Crick Institute says there is 'little to no evidence' that eggs from women seeking infertility treatment lack quality mitochondria.
IVF success rates fall sharply with age — from 26% live births per first transfer for women aged 35–37 to 8% for those 41–42, per 2024 U.S. statistics — which is what makes the promise of 'young mitochondria' alluring. A Kyiv clinic, BioTexCom, offers packages starting at €6,500. Only a handful of studies have examined MRT for infertility: a 2023 study of 25 people had no control arm and its lead author says no conclusions can be drawn; a 2019 study of 30 participants reported a single birth and did not recommend the procedure. Experts say the therapy should be offered only inside clinical trials.
