Bioethics Blogs

The Truth about Mitochondrial Replacement

Françoise Baylis disputes popular descriptions of mitochondrial replacement as much needed treatment to avoid the birth of children ‘born to suffer’.


The United Kingdom’s House of Commons recently voted to amend the Human Fertilisation and Embryology Act 2008 to permit heritable genetic modification using a technology called mitochondrial replacement. This technology involves the creation of an embryo using the genetic material from three individuals: a man who contributes nuclear DNA; a woman who contributes nuclear DNA; and a woman who contributes mitochondrial DNA.

Usually, embryos are created using the sperm of one man and the egg of one woman. The sperm contains nuclear DNA and the egg contains both nuclear and mitochondrial DNA. Some women, however, have diseased mitochondrial DNA. If these women reproduce, they could pass their mitochondrial disease along to their children. This could mean serious health problems for these children including neurodegenerative disease, stroke-like episodes, blindness, and muscular dystrophy. To avoid the birth of children with these types of mitochondrial diseases, scientists want to replace the woman’s unhealthy mitochondrial DNA with healthy mitochondrial DNA from an egg donor, and then create a healthy embryo using IVF. The donated mitochondrial DNA would be passed on to the children, and the children’s children, and so on for generations. This vertical transmission of mitochondrial DNA from one generation to the next has given rise to the debate about the ethics of heritable genetic modification.

In the wake of the House of Commons historic vote (382 to 128 in favour of amending the Human Fertilisation and Embryology Act), Gillian Lockwood, the medical director of the Midland fertility clinic, maintains there is a need to educate those who still “have anxieties” about mitochondrial replacement technology.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.