Parents who are at risk of passing on an inherited genetic disease can use Pre-Implantation Diagnosis (PGD) to reduce the risk of having a child affected by the disease 

PGD involves the testing of embryos produced through in vitro fertilisation (IVF). Where available, it is highly regulated and only permitted in stringent circumstances, and health authorities in respective countries determine the list of serious genetic conditions for which embryos can be tested.

The main challenging ethical dilemma in PGD is not so much when embryos are diagnosed with conditions that are not compatible with life but rather when they are diagnosed with genetic abnormalities which, although compatible with life, are considered undesirable by prospective parents, legislation and society.

In England and Wales, conditions such as Down's Syndrome and deafness, which are compatible with life, are included in the list for which PGD embryos can be tested. The embryos identified to carry any of the conditions I mentioned (Down's Syndrome and deafness) cannot be implanted: it is prohibited by law. Essentially, we have the technology that allows us to decide who we bring into existence and to eliminate disabilities.

In this series of articles - which will sometimes, and in parts, take the shape of conversations - I will be using the fictitious story of Mary and Giles. Their story will help us explore the different ethical questions we are likely to think about when selecting embryos for implantation. This is their story:

In Nomaland, after several failed pregnancies, Mary and Giles decide to undergo IVF procedure and elect to have PGD. They learn that, from the two embryos available for implantation, one of them would produce deaf children. Mary and Giles have to decide which embryos to implant: in Nomaland, there are no restrictions on what embryo you implant. Mary and Giles tend to disagree on everything, from the right way to hang a roll of toilet paper to how to make the perfect bed. They only agreed on one thing: the name of the child. Irrespective of the child's sex, that child will be named Charlie.

Back in the car driving home, Mary and Giles have one of the first conversations on the subject. It goes as follows:

Mary: If we are to choose to implant the embryos which will result in a deaf child, would we be to blame for inflicting harm and pain on that child?

Giles: I don't think it is a fair question to ask. The resulting child could not have been born in any other way.

Mary: What do you mean?

Giles: Let me explain. Let's call the embryo carrying the genetic condition of deafness X and the other one Y. If we decide to implant Y, the possible resulting child from embryo X will never come into existence.

Mary: I know what you mean, but if we decide to have a deaf child, isn't that the same thing as deliberately deafening a child? If we would not deafen a child or seek remedies to treat a deaf child, we must take issue with implanting a deaf embryo.

Giles: That is a legitimate and attractive argument. In my mind, however, I have always associated harming someone with making that individual worse off than they were before. If, as a result of a punch, I left someone deaf, that person will have gone from being a hearing, able-bodied person to a non-hearing, able-bodied one.

Mary: But say I would not want to become deaf and I have a preference that my children are not born deaf. If, because of a genetic defect, they are born deaf, wouldn't I be harming them?

Giles: Your preference is exactly that, a preference. Having a child who does not meet your preferences does not infer that they have been harmed. Remember, the child is born in the only condition in which it could have been born.

Stepping back from this conversation, some of us may share the concerns of the prospective mother. We may be uneasy with Giles's answers and feel that it is wrong to implant a deaf embryo. But is our uneasiness warranted?

If a 14-year-old tells us that she wants to get pregnant, we would ask her to wait until she grows older so that she would be able to give her child a better start in life. We would tell her that the child would be disadvantaged because of the possible bad start she would have given it.

Nevertheless, we would have to agree that, if she waits and conceives later in life, the child she brings into existence would be a different person altogether. Any objective we might have towards when one should conceive will ultimately affect who is born. One may also argue that bringing into existence a child at such a tender age, or a child with a disability, we would be harming the world as a whole.

However, if we accept our intuition as a justification in its own right, we would effectively be saying that our intuition is a moral obligation. This is a position which some philosophers and academics support but which has, over time, been heavily criticised.

All of us expect and hope that parents act in a way that promotes the welfare of their child. However, different prospective parents may - and often do - have different views as to what type of child would have the best life. Parents may exercise an internal perspective where they transpose themselves into the possible life of the resulting child. They may also apply an external perspective exercise which requires them to see themselves in the future life of each possible child. But can their reflection warrant a moral obligation?

Both exercises inherently imply that it is possible to measure what makes a good or a bad life. However, in this case we are measuring life against a subjective gradient, against what we see and have lived through­. While PGD gives us an indication of the physical and mental abilities of the resulting person, it will not tell us whether they would have a good or bad life. Those who are able-bodied may perceive children with disability as having a disadvantage in life. This may not, however, be the reality of children and people living with a disability. Our preferences are just that, preferences.

In the next piece, we will see Mary and Giles at a coffee shop chatting away with a relative of theirs who has been actively campaigning for the non-medicalisation of disability. 

Dr Mark Josef Rapa holds a Doctor of Laws degree from the University of Malta and Master of Laws degree in Health Care Ethics and Law from the University of Manchester.  [email protected]