During a feisty give-and-take with reporters at Rome's Foreign Press Club, he repeatedly declined to say where the mother was living, citing the need to protect her. "I receive a lot of threats," he said.
Antinori - who in 1994 helped a 62-year-old Italian woman become the oldest new mother in history - is part of a consortium of doctors that announced last year it would attempt human cloning. In April, he told an interviewer the group had successfully implanted cloned embryos in three women.
Yesterday, Antinori said the mother of what would be the first human clone ever born was 33 weeks pregnant. "I expect it during the first week in January," he said. "An absolutely healthy baby will be born." He said ultrasound scans - which he did not provide - indicated the fetus weighed between 5.5 and 5.9 pounds.
With all the bombast he could muster, Antinori also blasted the Vatican, which has roundly condemned him, and expressed concern that the Italian secret services might put a tail on him. He scolded a German reporter, complaining that German newspapers had likened him to Adolf Hitler. And he accused a rival scientist of planting a spy in the consortium.
Asked why he supported human cloning, Antinori, who runs a private fertility clinic here, said millions of infertile couples could benefit from the technology. In April, he was quoted in Rome's Il Tempo newspaper as saying that the most developed of the three fetuses came from the cell of a wealthy Arab man. At other times, he has said the two other women pregnant with clones were in former Soviet republics.
Cloning is designed to create the genetic twin of a life form. Scientists remove the DNA from an egg cell and insert the DNA from the adult being cloned. If it works, the egg cell begins to divide and grows into an embryo, which then can be transferred to a female and carried to term.
In the five years since the cloning of the famous sheep Dolly, scientists have duplicated a variety of animals. But because of the risks of severe abnormalities and other ethical considerations, most industrialized countries, including the United States and Italy, have banned human cloning.