The Vatican has condemned the cloning of human embryos, calling it the "worst type of exploitation of the human being".
"This ranks among the most morally illicit acts, ethically speaking," said Monsignor Elio Sgreccia, president of the Pontifical Academy for Life, the Vatican department that helps oversee the Church's position on bioethics issues.
A US company said it used cloning technology to make five human embryos, with the eventual hope of making matched stem cells for patients.
If verified, the team at Stemagen Corp., would be the first to prove they have cloned human beings as a source of stem cells, the master cells of the body - which scientists hope to harness to repair devastating injuries and cure diseases.
Sgreccia said the cloning research was unjustifiable. He also said it was unnecessary, given advances in similar research that bypasses the controversial use of embryos.
"There isn't even - I won't say the justification, because it's never justified - but not even the pretext of finding something (new)," he told Vatican radio.
There are several types of stem cells. Embryonic stem cells, made from days-old embryos, are considered the most powerful because they can give rise to all the cell types in the body.
Other teams have made stem cells they believe are similar to embryonic cells using a variety of techniques, including reprogramming ordinary skin cells into what are called induced pluripotent stem cells.
Sgreccia said, given the alternatives, he could not understand why scientists wanted to use human embryos - which the Roman Catholic Church believes should be protected.
"You can't know any more if this is all a game ... done solely out of the desire to experiment on men and women," he said.
Stemagen Corp said it used a technique called somatic cell nuclear transfer, or SCNT, which involves hollowing out an egg cell and injecting the nucleus of a cell from the donor to be copied -in this case, the skin cells from two men.
It is the same technique used to make Dolly the sheep in 1996, the first mammal to be cloned from an adult.
