The Reverend Joanne Jepson has been given permission to seek a judicial review of the decision by West Mercia Police not to prosecute a woman who had an abortion of a foetus that would have been born with a cleft palate.

The current abortion law in England is the 1967 Abortion Act, as amended in 1990 by the Human Fertilisation and Embryology Act. A woman can have an abortion up to 24 weeks in pregnancy provided two doctors agree to her decision. In the period from 24 weeks until birth, a woman can have an abortion only if two doctors agree that there is a threat to the woman’s life or if “there is a substantial risk that if the child were born it would suffer from such physical or mental abnormalities as to be seriously handicapped”.

As the law currently stands, the issue is whether a cleft palate constitutes such physical or mental abnormality as to indicate that the child would be seriously handicapped. Cleft palates and cleft lips are largely correctable with early surgery and speech therapy; but they are sometimes part of a wider syndrome, which can include mental handicap. But this case draws attention to a much wider and more important point, which is that the current legal framework is based on a distinction which is irrational and intellectually unsustainable.

Whatever your view of abortion, the law we now have does not make sense. A foetus at less than 24 weeks can be aborted for any reason if the woman chooses, while a foetus which is older than 24 weeks can only be aborted in particular circumstances relating to the well-being of the woman or of the future child. In other words, in the law today, the current law grants greater rights to the foetus at 24 weeks; and from that point the rights of the mother are set against those of the foetus.

The reason that the law draws a distinction at 24 weeks is that this is the approximate time, with current medical techniques, after which a foetus might survive outside the womb. This is superficially attractive as a defining moment in foetal development, so much so that many commentators have appeared on TV in recent weeks contrasting the actions of the woman who has had an abortion after 24 weeks with the fact that in other circumstances doctors would go to considerable lengths to save a foetus of a similar age. But on reflection it is impossible to find a convincing explanation of why the viability or otherwise of the foetus outside the womb should be a determining factor in the rights that society does or does not accord it.

Here are two compelling reasons why the viability of the foetus should not determine the rights that it has:

• First, the viability of the foetus at any given stage of development depends on the state of medical technology. As science advances, so will our ability to keep a premature foetus alive. Eventually we may well be able to incubate a foetus entirely artificially, from test tube fertilization onwards. Are we to say that, when this happens, all eggs and sperm should be accorded rights, because they are “viable” outside the womb?
• Second, we conceive of human rights as universal, which implies that rights depend on the characteristics of the person or thing (eg ability to feel pain, consciousness) rather than on contingent facts about the world around. So a foetus with particular characteristics either has, or has not, rights that need to be taken into account, irrespective of the availability of medical techniques. Are we to say that a foetus in America has more rights than a foetus in Ethiopia, because health care in its neighbourhood is more advanced? No: this contravenes our notion that rights depend on inherent characteristics, not on the state of the world.

It seems to me that we have settled on the viability test (which currently gives us the 24 weeks threshold) because many people feel that a foetus does not have significant rights early on during a pregnancy; but that by the time it is born it has important rights, about the same as those of an infant. We therefore feel that there must be some point of transition at which it acquires these rights and, in the absence of a more convincing moment to choose, use viability to mark the transition.

But this is dangerous for two reasons. First, it obscures the real issues by introducing an irrelevant consideration. There may be good reasons for attributing rights to a foetus; but viability isn’t one of them. Second, and of more practical importance, viability will come earlier and earlier as science advances. If we maintain the current rationale, we will over time restrict more and more a woman’s right to abortion.This may be what the anti-abortion lobby intends, of course.

But whatever we decide about abortion, we should do so on a rational and consistent basis, and not on an illogical and unsustainable boundary line.

If you want to read more about the moral philosophy of abortion, I recommend Causing Deaths and Saving Lives by Jonathan Glover, now a Professor of Ethics at Kings College, London. This book is humane, logical and very well written, and helps you not only to think about abortion, but also to apply philosophical thinking to other moral issues.