Mitochondrial Replacement Therapy (MRT) has become a fascinating and controversial field in regenerative medicine, as it promises to address inherited mitochondrial diseases. Over the decades, this technique has evolved thanks to the work of visionary researchers and has witnessed significant milestones in its development. This article will explore MRT, from its definition and the pioneers who have promoted it, to its history, global regulations and the ethical considerations that surround it.

Exploring Mitochondrial Replacement Therapy

MRT is an innovative technique designed to treat mitochondrial diseases by replacing defective mitochondria with healthy ones. This process involves the manipulation of eggs and embryos, and its essence lies in mitigating the hereditary risks associated with mitochondrial disorders. Pioneers in this field, such as Dr. Shoukhrat Mitalipov of the OHSU Oregon National Primate Research Center, have been instrumental in the advancement of MRT.

History and Evolution of Mitochondrial Replacement Therapy

The history of MRT dates back to the first pronuclear transfer experiments in the 1980s, but it was in 2016 that a significant milestone occurred with the birth of the first baby conceived using this technique. Dr. John Zhang, founder of the New Hope Fertility Center in New York, led this revolutionary process.

Zhang and his team used MRT to prevent the transmission of a specific mitochondrial disease from the mother when conceiving the first “three-parent baby”. This event marked a momentous advance in the clinical application of MRT and sparked ethical and scientific debates at a global level.

Another notable researcher who has contributed to the evolution of MRT is Dr. Doug Turnbull, Professor of Neurology at the University of Newcastle, who has played a crucial role in the development of techniques related to mitochondrial transfer in the United Kingdom.

Regulations and Legislations Worldwide

Regulations and legislation regarding MRT vary significantly around the world. In 2015, the United Kingdom became the first country to approve it for clinical use under strict regulations. However, in other places, the situation is more complex.

In the United States, the Food and Drug Administration (FDA) has taken a cautious approach. Although proposals have been discussed, MRT has not yet received approval for widespread clinical use.

In China, where the first birth by this therapy took place, regulations are less clear, underscoring the need for global harmonization in this field.

The regulations have also been the subject of ethical debates. In the UK, authorization is granted on a case-by-case basis, assessing the severity of the mitochondrial disease and the associated risks. This approach allows a balance between medical innovation and ethics.

Ethical Considerations

TRM is not without significant ethical challenges. Germline genetic modification, an intervention that affects inherited genes and potentially alters the genetic chain of future generations, raises fundamental questions about reproductive autonomy and the responsibility of scientists and society in making decisions that will impact inheritance genetics.

The concept of “three-parent babies” adds ethical complexity. MRT involves the genetic contribution of two parents and a mitochondrial donor, redefining traditional notions of descent and kinship. This raises questions about the identity and genetic relationship of individuals born using this technique, as well as the role of mitochondria donors in creating new lives.

Informed consent becomes a crucial component in the ethical context of MRT. Future parents must fully understand the risks and benefits of the therapy, as well as the possible implications for the health of their offspring, since we do not yet know how it could affect the long-term health of people born through this therapy. It becomes a vital ethical challenge to ensure that consent is truly informed and not influenced by external pressures.

Additionally, MRT raises questions about equity and access to this technology. Who will have the opportunity to benefit from MRT? Will social divisions be created based on the ability to access genetic modification of offspring?

The ethical consideration of embryo loss in the research and application of this technique is also a crucial dilemma. In the research phase, experimentation and refinement of the technique often involves the use and, in some cases, the loss of embryos. This aspect raises ethical questions about the value attributed to embryonic life in pursuit of scientific advances.

In the clinical application of MRT, where the process involves the selection and transfer of healthy embryos, the loss of embryos can generate moral conflicts, so ethical reflection becomes essential to balance scientific advances with integrity and respect for life in its early stages.

Therefore, MRT, although promising in the medical field, demands constant ethical reflection to safeguard the principles that define our humanity and the genetic integrity of future generations.


Patricia Sara Espinosa Civera

Luis Miguel Olcina Benedito

Medicine students – Catholic University of Valencia


Bibliographic references:

  1. Zhang, J., Liu, H., Luo, S., Lu, Z., Chávez-Badiola, A., Liu, Z., … & Mitalipov, S. (2017). First live birth using human oocytes reconstituted by spindle nuclear transfer for mitochondrial DNA mutation causing Leigh syndrome. Fertility and Sterility, 107(1), 29. Available in:
  2. Craven L, Elson JL, Irving L, Tuppen HA, Lister LM, Turnbull D, et al. Mitochondrial DNA disease: new options for prevention. Hum Mol Genet [Internet]. 2011 [Accessed: 14th December 2023];20(R2): R168–74. Available in:
  3. Honors Ethical Issues, Choices L. Florida state university libraries [Internet]. [Accessed: 14th December 2023]. Available in:,is%20an%20innocent%20human%20being
  4. Committee on the Ethical and Social Policy Considerations of Novel Techniques for Prevention of Maternal Transmission of Mitochondrial DNA Diseases, Board on Health Sciences Policy, Institute of Medicine, National Academies of Sciences, Engineering, and Medicine. Mitochondrial replacement techniques: Ethical, social, and policy considerations. Claiborne A, English R, Kahn J, editores. Washington, D.C.: National. Academies Press; 2016. Available in:
  5. Wolf DP, Mitalipov N, Mitalipov S. Mitochondrial replacement therapy in reproductive medicine. Trends Mol Med [Internet]. 2015 [Accessed: 14th December 2023]; 21(2):68–76. Available in:
  6. Connor S. UK becomes first country in world to approve IVF using genes of three parents. Independent [Internet]. el 28 de junio de 2013 [Accessed: 14th December 2023]; Available in:
  7. “Three parent” technique must not be marketed in US, says FDA. New scientist (1971) [Internet]. [Accessed: 14th December 2023]; Available in:


Subscribe to our newsletter:

We don’t spam! Read our privacy policy for more info.