Pornography perverts all sorts of private human activities for voyeuristic gratification so it should not be surprising that pregnancy and even childbirth have attracted the pornographers' interest. Nevertheless it will have astonished and appalled most people that a film-maker could even think of using somebody's birth for a prurient purpose. It is doubly dismaying that the baby's mother is an enthusiastic participant in the project.

Health Minister Annette King has done the right thing in refusing permission for the film to be made in a public hospital, al though she has effectively overridden orders of the High Court, which would have allowed the film to be made on condition the baby was not seen. The court's decision was plainly unsatisfactory; its intention to protect the interests of the child would not be satisfied by a film depicting everything except the baby.

Child, Youth and Family Services, which sought guardianship of the unborn baby in order to stop the filming, argued that the child was likely to be harmed by association with the film. "The baby faces the prospect, locally at least, of growing up being known as the 'porn baby'," said Deputy Solicitor-General Helen Aikman. That sounds very likely because there seems to be no argument the film would break new ground. The baby's mother had told a magazine: "Ever since I was a stripper I dreamed of starring in a porn movie. But I never thought I would become the first person in the world to give birth during a porn film."

Plainly the court's order would not save her child from the stigma of her achievement. The baby might not be seen but could forever be identified by association with the "star" of this pioneering production. It might be saved from that fate only if childbirth became standard pornographic fare, and that must not be allowed to happen.

To stifle this trend requires a better argument than that presented to the court. Pornographic depictions of childbirth will not become acceptable even if the child can be protected from later embarrassment. Society needs to declare from the outset that such treatment is beyond the bounds of decency because it offends our fundamental human respect.

Granted, all pornography does that to a degree, but good law is often a matter of degree. The laws against indecent publication cannot be too definitive. Everything needs to be assessed in its context. A blanket prohibition on the filming of childbirth, for example, could prevent people recording the event for innocent private and family wishes. It is possible that a sensitive and tasteful recording of a real birth could feature in a film for public commercial release. These things happen in the name of art.

But most people have no difficulty distinguishing pornography when they see it. The difficulty is not in defining what is offensive but in preventing it taking advantage of laws that preserve the liberties of the innocent. We are lucky in this case that those involved in the film do not pretend that it is being made for private use. If they did it would be hard for anybody to stop them.

As it is, they might yet take advantage of the court's conditional approval by going outside a public hospital. With a compliant midwife, which the mother seems to have, and with no complications, the film could easily be made of a home birth or possibly in a private hospital that did not mind the risk to its reputation. Ultimately these films can only be policed by post-production censors. But with a strong assertion of some principles of common human decency, we might hope to stop them at birth.