I HAVE done many interviews about abortion, but one that stays with me most vividly was a conversation with the late Professor Peter Huntingford, an ardent pro-choice campaigner and distinguished obstetrician and gynaecologist.

He said that he passionately believed in a woman’s right to choose, and yet — “there comes a time when it is just too late to terminate a pregnancy”. He then added, with a rather tormented expression: “I know that we can do abortions too late, because I’ve done them too late.”

Once you get past the 20-week gestation point, the operation becomes increasingly distressing because it is so obvious that you are destroying a very small human being. And yet, he had had pregnant women in his surgery who reacted furiously when he said that it was too late — for him — to terminate. Women said it was “illogical” that they could have had an abortion a week previously, at 23 weeks, but not now, at 24 weeks. “Yes, it is illogical,” he conceded. “But that’s the way it is.”

One of our problems today is that we discuss abortion far too much in terms of rights, and far too seldom in terms of nature. Nature works by development: and nature does not award rights. The pregnant woman who cannot understand why she is entitled to have an abortion at 23 weeks, but not at 24 weeks, has been over-exposed to the rights culture, and under-educated in the laws of nature. Nature takes its course, and there comes a moment when it is just too late, in life, as in death.

Legal limitations on abortion are always in some sense arbitrary, yet there are nature-based changes which signal particular junctions in pregnancy. Between 12 and 13 weeks, the foetus doubles in size, and that is a limitation observed by some legislatures. Between 16 and 18 weeks, the mother feels the unborn move; that is another limitation observed. Sweden, which was the first country to legalise abortion, and is regarded as progressive, sets a limit of 18 weeks on abortion practice, except for grave medical reasons.

It is good that the Archbishop of Canterbury should enter the debate, proclaiming that abortion is a serious matter for Christians, and that it should be part of political discourse. Yet, it seems to me, it is also important to point out that nature’s processes are not a matter of rights, or even choices: but of development and time.