In June the United Kingdom took the first step towards drafting the legislation, to be discussed in parliament, to approve the testing of an IVF procedure which creates what are colloquially being called ‘3 parent babies’.
I agonised over writing that first sentence because having read the comments on most articles published about this topic, I really wanted to try and avoid a repetition of the inane, knee-jerk responses these types of writings generate. Some people are all for it, regardless of what it is about, simply for the sake of the advancement of science or to help those parents who cannot have healthy babies naturally. Others are all against it because it is evil, macabre and opens the way to designer babies. Both extremist opinions spewed forth without taking time to evaluate what approving the application of such a technology really entails.
A little background science is needed to fully understand the implications. (Apologies to those who already know the science…) Genes, those bits of DNA which are responsible for our characteristics, and which make us the biological offspring of our parents, are inherited equally from the father and the mother. The mother also supplies what is called mitochondrial DNA. These mitochondria are the powerhouse of each cell, responsible for the generation of energy within the cell. They also contain DNA. Sometimes this DNA has mistakes (mutations) in which case a number of lethal diseases may develop. Since mitochondrial DNA only comes from the mother, its effects cannot be diluted out by the father’s DNA, and so, if the mother has the mutation, the child will almost always get the disease.
That leaves the parents with 3 options:
– try for a child and hope for the best, knowing that it is unlikely to have a healthy child
– make use of an IVF technique that will genetically engineer the baby, transplanting the nucleus containing the DNA to a healthy donor egg cell
And this is what ‘3 parent babies’ is all about. Take an egg from the mother and sperm from the father, fertilise the egg in vitro and take out the nucleus leaving behind the defective mitochondria. Transfer the nucleus to a healthy donor egg from an unrelated female and culture the embryo in a Petri dish until it starts developing, test it and if it is all OK transfer it to the mother’s womb.
And this is why I agonised over the writing of that first sentence. This is still an experimental procedure; in principle it works. Someone somewhere has tried it out and found it is possible to transfer the nucleus and establish an embryo using the donor’s egg but no one has seen if said embryo will go to term. Whether after all that manipulation the resultant baby will be healthy and free from other defects caused specifically by that same manipulation. Whatever a government discusses and approves (or otherwise) cannot be implemented in a clinic before all this testing is carried out, numerous times, to establish whether it is safe or not; and all this testing means using and discarding a number of human lives.
Eventually any number of couples who have lost children to mitochondrial diseases may benefit, but this will only be eventually. So before we all jump on the band wagon we should think of all the steps that need to be taken before a procedure such as this can be safely applied clinically.
By the way, there is another procedure which uses a ‘spare’ IVF embryo instead of an unfertilized egg as the mitochondrial donor.