Paul Vallely: Better an abortion than a mass grave?

The Roman burial of unwanted babies and new evidence on foetal pain make us think again about the start of a child's life

Even 2,000 years on there was something disturbing about the discovery of the bones of 97 new-born babies at what archaeologists believe was a brothel in a villa in Roman Britain. Infanticide, apparently, was the only reliable form of contraception for a Roman sex worker. In any case, historians suggest, the killing of unwanted newborns was not so shocking in ancient times as it is today. Infants were not considered to be full human beings until they were about the age of two, which is why infants that age were not buried in cemeteries but at domestic sites in the Roman era.

Leaving an unwanted child out on the hillside, at the mercy of the weather and the wolves, has been practised on every continent and by people from every level of civilisation. Rather than being an exception, anthropologists think, infanticide has been a norm. In places it still is. Amartya Sen wrote of the "100 million missing women" in contemporary Asia; as many as 40 million baby girls have been killed in modern-day China, to judge from the population imbalances.

All this suggests that some of our intuitive ethical responses are culturally specific rather than innately moral. Attitudes shift. And there are signs that they are shifting in contemporary society on the issue of abortion. The report from the Royal College of Obstetricians and Gynaecologists on the age at which a foetus can be said to feel pain is the latest indicator of that.

The report was something of a blow to those politicians seeking to reduce the upper time limit for having an abortion, which is currently at 24 weeks of a pregnancy. Before the election, David Cameron indicated that he would back moves to reduce the limit to 22 weeks – which some MPs tried, without success, to do in 2008 when parliament last voted on the issue. But last week's report suggested that the nerves of a foetus are not fully connected to its developing brain by 24 weeks, so it cannot be said to experience pain. The chemical environment in the uterus, in any case, induces "a continuous sleep-like unconsciousness or sedation".

We have not heard the last of this yet by any means. Two things have changed in recent times. Abortion has increased almost tenfold since it was legalised in 1968, and the grounds on which it can be obtained have become far less restrictive. And advances in medicine mean that babies can now survive outside their mother's womb at 24 weeks, when abortion would still be legal. The debate has been dramatised by new, 4D ultrasound techniques, which reveal foetuses of only 12 weeks sucking their thumbs and apparently showing facial expressions, and by the fact that couples now routinely come home with a proud photo of their baby at the 12-week scan.

The key question is whether any of this has altered the morality of the issue. It has not for those at the extremes of the argument. Those who are "pro-choice" insist that a woman always has the right to determine the fate of her own body and the foetus within it. Those who are "pro-life" insist that even a one-day-old fertilised egg is a human being with equal and indivisible human rights.

But neither of these absolutist positions chimes well with the pragmatic attitude of the majority of the British public whose judgement rests on the two key questions emphasised by the new technology – when is a child capable of autonomous life outside its mother and how much pain can a foetus feel.

Science appears to be changing perceptions on this. In hi-tech hospitals, as many as 80 per cent of babies born at 24 weeks survive, as do half the 23-weekers. There is an incongruity about the idea that such children can be in intensive care on one floor of a hospital, while foetuses of the same level of development are being aborted on the next. The fact that we call one a baby and the other a foetus conjures an existential definition out of whether a child is wanted or not.

The cognitive dissonance this induces in medical staff perhaps explains why nationally there is a declining number of doctors prepared to carry out abortions. Others are fixing their own limits about the number of weeks at which they are prepared to abort.

"Beyond a certain point, it just looks too much like a baby," one doctor who regularly performs abortions told me. And beyond a certain size, the foetus has to be cut up inside the womb, and its skull and pelvis crushed, to get it out. Many NHS trusts now do not have any staff willing to perform abortions much after 12 weeks.

The new report on foetal pain takes the argument in a different direction. If connections from periphery to cortex are not intact before 24 weeks, and if, as most neuroscientists believe, the cortex is necessary for pain perception, many people may feel comfortable with retaining the 24-week limit.

There are a few "ifs" in that, however. Those same people might not feel as comfortable following through the logic to the removal of the current legal requirement in all post-22 week abortions in the UK for the foetus to be either injected with a drug to stop the heart or put under a general anaesthetic.

The argument that a foetus cannot really feel pain until after birth, when the sedative environment of the womb is replaced by the stimuli of the outside world, sounds more philosophical than medical, and opens up as many questions as it provides answers. So does the apparent suggestion that any practice that is devoid of pain is morally acceptable. We would not think it was all right to get rid of unwanted, non-consenting old folk so long as they were sedated first and felt no pain as they were dispatched.

Of course, most of the British public do not see a moral equivalence between a developing foetus and a living person. A foetus is human life but it only gradually becomes a human person. That is why it was received with distaste when a Scottish cardinal talked about the number of abortions as the equivalent of two Dunblane massacres every day.

To most of the public, taking the morning-after pill is not the same as looking into the eyes of a six-year-old child and blowing her head off. Even if they are uneasy about the growth of abortion as a casual alternative to contraception, they feel there are times when abortion is morally preferable to the alternative. They reject the oversimplification of the debate into "pro-choice" and "pro-life" polarities.

It is often said that there is no middle way over abortion. Advances in science suggest otherwise. Other European countries have, for example, made abortion far more available in the early weeks – but they have brought down the limit in later weeks, unless the foetus is severely disabled or the mother's life is at risk. In Britain, around 89 per cent of abortions are in the first 13 weeks. Only 2 per cent are between 22 and 24 weeks.

All this is not a re-run of the old argument on abortion. Something has shifted. But it is not quite clear yet exactly what.