Healthy three-parent babies: but does the end justify the means?

Recently, British media celebrated the birth of eight babies using a groundbreaking genetic technique designed to prevent the transmission of certain hereditary conditions. Headlines hailed it as an unqualified success: eight healthy children, spared the prospect of devastating illness. But this achievement comes at a profound moral cost, one that has been almost entirely absent from the public conversation: the new technique involves the destruction of human life.

The method, known as mitochondrial replacement therapy (MRT), uses genetic material from three people. In 2015, the UK became the first country to legalise it, with the stated aim of preventing maternal mitochondrial diseases, rare but potentially fatal disorders caused by faulty mitochondria.

Mitochondria are tiny structures in our cells that we inherit from our mothers. In MRT, scientists use two fertilised human eggs: one from the intending parents, which carries defective mitochondria, and one from a donor woman with healthy mitochondria. The nuclear DNA, which determines personal traits like appearance, personality, and height, is removed from the parents’ fertilised egg and transferred into the donor’s fertilised egg, after the donor egg’s own nucleus has been removed and destroyed. The resulting embryo has nuclear DNA from the mother and father, and a small amount (less than 1%) of mitochondrial DNA from the donor.

Although this might appear to be a compassionate use of science to prevent suffering, it involves practices that are gravely unethical.

First and foremost, the process requires the creation and destruction of multiple human embryos. Each embryo is a human being with inherent dignity and the right to life from the moment of conception. Discarding or experimenting upon embryos is, therefore, morally unacceptable.

Secondly, the technique entails altering the DNA in such a way that changes will be passed on to future generations (germline genetic modification). This raises profound moral questions. Once we begin to manipulate the genetic makeup of human beings at the embryonic level, where do we draw the line?

For this reason, mitochondrial replacement therapy is banned in countries such as the US, Germany, France, Italy. In Ireland, the Assisted Human Reproduction Act 2024 includes a clear ban on mitochondrial replacement, but the Act is not yet commenced.

Although the term “three-parent baby” is often used in the media, it is a bit inaccurate. Personal genetic characteristics like appearance, personality, height, eye colour, or intelligence are not passed on through mitochondria. Yet mitochondrial replacement therapy still introduces a third genetic contributor, raising complicated ethical and legal questions about parenthood.

Medical science must always serve the integral good of the human person, respecting both physical life and moral law. While the desire to prevent illness is good and understandable, not every technologically possible solution is morally permissible. The ends do not justify the means, especially when those means involve the destruction of human lives, however early in development.

Moreover, these new techniques reflect a worrying trend in modern biotechnology: reducing human beings to a set of biological components to be manipulated, optimised, or discarded. Such a view undermines the sanctity of life and the unique, irreplaceable value of each person.

Analysis Stock photo by Vecteezy