December 31 2000 FAR EAST
Clone scientists can grow sperm in laboratory
Cherry Norton and Lois Rogers
SCIENTISTS have succeeded in growing sperm in a laboratory for the first time, paving the way for infertile men to produce their own genetic offspring.
The team, from the Machida district of Tokyo, also believe they will be able to reprogramme male cells into producing eggs so that men can both father and "mother" children. This could allow gay men to be parents together.
At the moment the technique, which clones embryo cells and turns them into sperm, has been attempted only with mice. But the researchers plan to test the techniques on adult men. Although cloning humans is banned under Japanese law, the new technique gets round the restriction because it uses cloning to produce the seed for a new baby rather than the baby itself.
The development has been condemned by medical ethics groups as a further step in the "brutalisation" of modern science. They believe it risks turning human life into a commodity with no limits on the experimental techniques for which it can be used.
The new technique was disclosed at a recent biologists' conference in Japan and will be unveiled to the international scientific community in a publication next year.
Poshiaki Nose, of the Mitsubishi Kasei Institute, described last week how he had worked out which of the cells in early embryos were destined to grow into the baby's germ cells - sperm or eggs.
In the early days after fertilisation, the embryo is a mass of so-called stem cells, each programmed to develop into a different part of the body. Nose's technique involves using genetic markers to work out which cells have the genes involved in sperm manufacture "switched on".
He has grown these cells into sperm in the laboratory before they are implanted back into the testes. They appear genetically normal.
"We have no reason to doubt that these sperm are viable," Nose said. "The stem cell-derived sperm are exactly the same as those produced by the testes and we are now seeing if we can make them fertilise normal eggs."
Other researchers noted that the Japanese team had yet to produce a
healthy baby, but few doubt they will be successful.