The recent speech by the Archbishop of Dublin, Dr Desmond Connell, to the Life Society in Maynooth has earned him a torrent of criticism. The ambiguous expression of his thoughts on the notion of the "wanted" child was wide open to misinterpretation and caused understandable upset.

On the other hand, the bulk of the criticism was not an exercise in reasoned argument but personal adhominem attack: he was insensitive, as a celibate he must be ignorant, the Catholic Church is discredited anyway etc, etc.

The exception was Garret FitzGerald's thoughtful critique in this newspaper last Saturday. Dr Connell is supposed to have said that the "wanted" child is the "planned" child, and the "planned" child is going to be treated as a mere technological product, hence, a problematic child, so it is wrong to "plan" children.

But texts have to be interpreted fairly. He could not have meant that it was wrong for couples to plan their family, since the encyclical Humanae Vitae itself supports planning one's family, nor did he say that children resulting from such planning were mere products. He did say: "A profound alteration in the relationship between parent and child may result when the child is no longer welcomed as a gift but produced as it were to order."

The emphasised words bring out the point that his remarks do not apply to couples who see their child as a gift. Strictly speaking, he was not speaking to or about individual couples and parents or about their children, so demands for empirical evidence are off the point. He was ad dressing society about the future impact of reproductive technology on human relationship and the moral implications of its uncritical use.

He was thinking of the growing phenomenon, in the United States and elsewhere, of marketing sperm and ova to customer specifications.

He was echoed by a professor of law in Chicago, who was quoted in the International Herald Tribune (March 4th 1999) as saying: "I think we are moving to children as consumer products." However, to say that there is a communication gap here is an understatement. Can anything be learned from the episode?

The Catholic Church's teaching on poverty, inequality and immigrants is easily understood, since it is in line with the cultural values of Irish society. Its teaching on sexuality is not in line with Irish culture and, as that culture changes, the sexual behaviour patterns have changed radically and unprecedentedly since 1960.

To give one example: in the UK, the single parenthood rate was 5 per cent in 1961, virtually unchanged since 1800; by 1995 it had reached about 30 per cent. Ireland and other countries are no different in this regard. As has been noted by several commentators, nobody really understands the causes of this revolution or its long-term implications.

Communication depends on the channel being open at both ends: the church needs to improve its communication skills, but the present cultural climate makes it very unlikely that the Catholic view of sexuality would be understood anyway. Yet the Catholic position on sexuality should be interesting, since it is either quite insane or deeply prophetic.

Turning to that teaching, the core issue is: what is sex for? It is well known that Catholic teaching accepts natural family-planning methods (Billings, rhythm etc), but the natural/artificial distinction does not capture the point of the teaching. It should be interesting to note that the church does not object to contraception in animal breeding.

The point of the teaching might be illustrated as follows: human life is sacred, hence, the human body is sacred too, it must not be violated or used as a mere means. The sacredness of the body applies particularly to sexual activity, because here the physical embodies the personal to a degree not found in other activities, e.g. in going walking or peeling the potatoes.

One's sexual acts are or ought to be intensely personal. To have sex without making love is to exploit the other and instrumentalise one's own body. Secular sexual ethics holds that my body is my property, to do with as I please. It is dualist, since it assumes that I am not my body.

The more holistic Catholic approach, that my body is part of me, rejects the secular view because it involves seeing one's body as a tool or instrument, hence not sacred.

Likewise, it holds that one ought not treat the bodies of others as mere means to one's own ends, even though one's ends or intentions may not be bad.

At this point, Garret FitzGerald asks the very reasonable question: if the intention (avoidance of pregnancy) is the same, how can the choice of the means (natural or artificial) make a moral difference?

The moral intuition or gut feeling which Paul VI tried to express in Humanae Vitae is that it does make a difference. The difference arises because this particular activity is the supreme, ultimate expression of personhood, of selfhood: the body must not be manipulated in this act for purposes other than those inscribed in the expressive nature or language of the body.

This is not a theological point: it is philosophical, although the kind of philosophical theories which might elaborate it are found largely in mainland Europe and hardly at all in the Anglo-American cultural world (of which we are increasingly a part). At the core of Catholic sexual ethics is concern about domination, instrumentalisation and depersonalisation of the body, for sensual or, more subtly, emotional gratification.

In this, it is at odds with the contemporary liberal market-driven ethos, which sees sexual relations as private, is desensitised to exploitation and has a consumerist obsession with choice.

It is also clear that such teaching assumes sexual fidelity, is addressed to couples and can be lived out only by couples fully committed to and co-operating with each other.

Thus, the Catholic objection to contraception is not about respecting biology and physical processes as such, but about respecting them insofar as they are designed to embody and express the person totally. It is because sex between human beings is not just reproductive activity or evolutionarily programmed animal coupling, but interpersonal encounter and giving of self, not just of body, that contraception is morally problematic.

One must respect the other's body because it is the body of a person, and that includes above all respecting its power to contribute to the procreation of a new person. A similar respect is required for one's own body.

Furthermore, the way in which contraception is marketed has suggested that abstinence, chastity or sexual self-discipline are now unnecessary, since contraception is a preferable and adequate substitute. Accordingly, the secular ethic says that any sexual activity between consenting adults must be presumed to be morally acceptable.

By contrast, the Catholic view is that technology cannot replace moral character and emphasises the importance of sexual self-discipline. This tended to be seen in the Sixties and Seventies as damagingly repressive, until growing awareness of sexual harassment and paedophile behaviour brought home to us that sexual self-discipline is, indeed, indispensable.

Western societies are going through a revolution in this area. Hopefully, a civilised debate can continue. It is necessary.

Seamus Murphy S.J. teaches philosophy at the Milltown Institute of Theology and Philosophy