... and now for the Tank Child

First it was conception in a test tube. Now medical experts are aiming to go one step further by creating entire artificial wombs.

In a move which has echoes of science fiction, a team of Japanese scientists, aided by British specialists, is experimenting with a high-tech tank in which a foetus would be able to grow to full term without its mother's direct help.

A dialysis unit and an artificial lung would in effect become the baby's mother as it lay suspended in artificial amniotic fluid. Such a development might allow a woman like Mandy Allwood, currently expecting octuplets, to keep them all without putting each one at risk.

The Anglo-Japanese project, centred in Tokyo and University College London, under Professor Mark Hanson, has already successfully experimented with a goat foetus and is confident that the technique could soon be applied to humans.

Scientists involved in the project believe the tank womb would have huge implications for saving very premature babies. In particular there could be implications for multiple births, where babies if they survive at all are likely to be tiny and exceptionally vulnerable outside the womb.

However, there would be grave ethical questions about the use of an artificial womb by women who simply didn't want all the traumas associated with the process of a full-term pregnancy.

Anthony Kaiser, a consultant neonatologist at St Thomas's Hospital, south London, said: "I do not see it as a substitute womb for people who don't want to be pregnant." Such a use might be ethically "unacceptable", he said, given that an artificial womb would be inherently more dangerous to a child than normal pregnancy.