ANOTHER adult stem cell breakthrough, and in Barcelona, no less:

Doctors have given a woman a new windpipe with tissue engineered from her own stem cells in what experts have hailed as a "milestone in medicine."

The breakthrough allowed Claudia Castillo, 30, to receive a new section of trachea -- an airway essential for breathing -- without the risk that her body would reject the transplant.

Castillo was given the stem cell surgery, the controversial branch of medicine that some say could lead to human cloning, after suffering a severe lung collapse.

The condition, caused by long-term tuberculosis left Castillo, a Colombian now living in Barcelona, unable to carry out simple domestic duties or care for her two children.

The only conventional option was a major operation to remove her left lung, a risky procedure with a high mortality rate.