Scientists have created stem cells from human male testicle cells.  Experts say the development may provide one more alternative to the controversial use of human embryonic stem cells to grow replacement tissue.  VOA's Jessica Berman reports.

Stem cells are known as "pluripotent cells", meaning they can be manipulated to grow into any cell in the body, potentially offering replacement tissue for a range of illnesses, including Parkinson's disease, diabetes and spinal cord injury. 

Human embryos are a rich source of stem cells, but the use of growing embryos is prohibited in the US and other countries, including Germany, because extracting the master cells destroys them.

So, researchers have been searching for alternative sources to embryonic stem cells that are just as versatile but without the controversy.

In a paper published this week in the journal Nature, German researchers report on the latest effort. By reprogramming the testicle cells of 22 males between the ages of 17 - 81, researchers are coaxing them to begin the process of becoming muscle, bone and nerve cells.

Thomas Skutella, a professor at the Center for Regenerative Biology and Medicine in Tuebingen, Germany, is the study's lead author.

Skutella says the extraction and manipulation of stem cells from germ cells which produce sperm, had previously been achieved in mice, prompting investigators to try the same experiments in humans.

"We were looking for pluripotent cells of different origin [than human embryonic stem cells].  And there were hints that those cells might be found in the germ cells which make sperm.  And it has been shown those cells might be pluripotent, so that was a starting point," Skutellla explained.

Unfortunately, experts say women would not benefit from the latest stem cell development.  But Skutella says a similar technique may be used to grow stem cells for women from egg cells.