Human cloning is a secretive business, not least because it is illegal in most countries on moral grounds. The scientific community also questions whether it is possible.
That a controversial American firm linked to a movement that believes extra-terrestrials created humankind has made the latest cloning claim does not help the debate.
Clonaid claims its researchers are on the verge of producing the world's first cloned human and that the next step, eternal life, could be a reality in 30 to 50 years. Its South Korean affiliate, the electronics company BioFusion Tech, last month announced that a woman was two months pregnant with a cloned embryo as a result of equipment it had developed.
Scientists in the mainstream scorn the claims. The director of the Centre for Bioethics at the University of Pennsylvania, Arthur Caplan, described Clonaid's announcement as 'very wacky'. He believed there appeared to be no supporting scientific evidence.
Clonaid is not the first to make such a claim. In April, Italian fertility specialist Severino Antinori said a woman involved in his human cloning programme was also pregnant and that three others not involved with his work - two in former Soviet republics and the other in an Islamic country - were bearing cloned human embryos up to seven weeks old.
Clonaid, which refers to itself as the world's first cloning company, takes the controversy a step further. It is connected with the Raelians, a science-based group which says it has 55,000 members in 84 countries.