European scientists have voiced scepticism about claims by the Italian gynaecologist Severino Antinori that one of his patients is two-months pregnant with a cloned human embryo.

Antinori, who is director of the infertility unit at the International Associated Research Institute for Human Reproduction in Rome, made the announcement to the newspaper Gulf News last week, when he attended a meeting on human genetics in the United Arab Emirates.

One Italian newspaper, Il Tempo, said that Antinori had confirmed the claim, but he has refused to comment to other journalists, saying only that “research needs silence”. Glasgow's Sunday Herald, meanwhile, reported that Antinori had split with his long-time collaborator, Panos Zavos of the Andrology Institute of America in Lexington, Kentucky, and that Zavos was pursuing his own cloning programme independently in Cyprus.

“There is, of course, some scepticism that the cloning has really been done,” says Carlo Redi, an animal-cloning expert at the University of Pavia. Although the work is alleged to have been done outside Europe, if it has taken place, he says, it contravenes both the law in Italy and normal codes of medical practice. Studies in animals have shown that cloning yields few successful births, and that a high proportion of the offspring produced are born with defects. The Italian Medical Association has issued several threats to expel Antinori, but has not yet done so.

Caution is also apparent outside Italy. “It is theoretically possible,” says Eckhard Wolf, a cloning expert from the University of Munich, but he adds that “even if Antinori has achieved a pregnancy, the rate of spontaneous abortion in the second trimester of pregnancy is very high, so comments are premature.”

More bluntly, Ian Wilmut of Edinburgh's Roslin Institute, a member of the team that cloned Dolly the sheep, says that Antinori's claim is “either a misunderstanding or deliberately misleading”. The biggest danger, he says, is that Antinori's activities will generate public anxiety about cloning, turning people against the idea of using 'therapeutic cloning' for regenerative medicine.

In Italy, scientists fear that the news could adversely affect the public mood just as a bill to regulate the use of embryonic stem cells and of therapeutic medicine is to be debated in parliament. “We worry that it may increase pressure for a very restrictive law,” says Redi.