🇩🇪 Deutsche Version: Drei-Eltern-IVF (Mitochondriale Spende)
Note: The ethical judgments on this page refer exclusively to the act — never to the person who performs it or who has come into being through it. Every child conceived through this procedure is a complete human person with full dignity from fertilization onward. Cf. Note on Ethical Judgments (German).
Mitochondrial Replacement Therapy (MRT), also known as three-parent IVF, is a form of artificial fertilization in which the cytoplasm of a donor — together with her mitochondrial DNA — is transferred into the egg of the intended mother. The aim is to prevent the inheritance of mitochondrial hereditary diseases. Two techniques are used: pronuclear transfer (after fertilization) and maternal spindle transfer (before fertilization).
Legally authorized in the United Kingdom in 2015 and clinically applied from 2023. In July 2025 the Newcastle Fertility Centre reported eight healthy live births out of 35 authorized treatments (NEJM, July 2025) — the first clinical evidence for the safety of mitochondrial replacement therapy.
Ontological classification
- is a subclass of: artificial fertilization
- presupposes: fertilization
- produces: a genetic three-parent constellation (~99.9% nuclear DNA from the intended parents, ~0.1% mitochondrial DNA from the donor)
Personal-ontological classification
The child conceived through mitochondrial replacement therapy is, from fertilization onward, a complete human person with full ontological dignity — its personhood stands, in no ontological sense, under the reservation of its mode of conception.
Ethical assessment
Three points appear problematic from a personal-ontological perspective:
- Germline intervention. The mitochondrial alterations are inherited — any intervention in the germline affects not only the treated person but also her descendants, who cannot consent.
- Third-party constellation. The child has genetic material from three persons. This realizes a particular form of fragmented parenthood — the unity of genetic motherhood is divided.
- Pronuclear transfer. In the predominant variant, the first fertilized egg is destroyed after fertilization; with it, an already existing human person (cf. surplus embryo).
Sources: Research status as of April 25, 2026.
Further sources:
- Hyslop, L. et al. (2025): Mitochondrial Donation and Preimplantation Genetic Testing for mtDNA Disease. New England Journal of Medicine. DOI: 10.1056/NEJMoa2415539.
- McFarland, R. et al. (2025): Mitochondrial Donation in a Reproductive Care Pathway for mtDNA Disease. New England Journal of Medicine. DOI: 10.1056/NEJMoa2503658.
- Human Fertilisation and Embryology Authority (HFEA) (2025): HFEA comments on the news that eight babies have been born after mitochondrial donation treatment. Press release, hfea.gov.uk.
- Greenfield, A. et al. (2017): Assisted reproductive technologies to prevent human mitochondrial disease transmission. Nature Biotechnology 35(11): 1059—1068.
- Nuffield Council on Bioethics (2012): Novel techniques for the prevention of mitochondrial DNA disorders: an ethical review. London.
- Bredenoord, A. L. & Braude, P. (2010): Ethics of mitochondrial gene replacement: from bench to bedside. BMJ 341: c6021.
- Congregation for the Doctrine of the Faith (2008): Instruction Dignitas personae on Certain Bioethical Questions (September 8, 2008).