Despite the scientific breakthrough that this procedure means, researchers are far from being able to create human babies as in science fiction film by Michael Bay "The Island" (2005).

In fact, the investigation was carried out with the idea of ​​creating mini-yo.En clones instead, sought to create stem cells to cure diseases.

 But the parallels between the process of cloning animals and humans have caused new alarm. Episcopal conferences in different countries quickly issued a statement condemning the investigation, both the destruction of embryos for research and the possible human reproductive cloning.

Fortunately for anyone concerned about the specter of human cloning, scientists say they are very far from being able to obtain cloned human embryos to overcome the early stages of development. Study leader, Shoukhrat Mitalipov at Oregon Health & Science University, told reporters that the early embryo - 100 cell masses known as blastocysts - appear to have defects that prevent implant properly in the uterus and mature.

Why then clone human embryos?

The answer is stem cells. These cells have the ability to become any tissue in the body - one that could turn culaidad the stars of regenerative medicine, and can thus obtain cells and tissues of patients suffering from various diseases.

Embryonic stem cells resulting from cloning can theoretically be grown until the adult cells to replace diseased cells of a patient.

While cloning is not the goal of this controversial new technique, scientists say it would be naive to ignore the fact that this discovery leaves a step closer to the ability to create human clones.

"My feeling is that it is a kind of an involuntary step in that direction," says Paul Knoepfler, a stem cell researcher at the University of California.

The worst case would be to create a clone before reaching draft legislation regulating this technique.

Picture has been released into the public domain by its author, Maltesedog at the English Wikipedia project.