Hamburg, Germany -- Faced with strict German laws banning the use of human embryos, a team of German scientists came up with a radical new "ethical" source for stem cells -- men's testicles.

The scientists believe their breakthrough may offer a whole new range of treatments for diseases like Parkinson's and diabetes and for spinal cord injuries involving use of men's own stem cells to replace damaged or diseased cells in their own bodies.

The researchers from the Universities of Tuebingen and Cologne in Germany, and King's College London, say that routine biopsies of men's testicles could provide a new source of stem cells, which could be as good as embryonic stem cells for researching and developing treatments for a range of serious diseases, but without the ethical and legal problems of embryonic stem cells.

"The generation of human adult germ-line stem cells from testicular biopsies may provide simple and non-controversial access to individual cell-based therapy without the ethical and immunological problems associated with human embryonic stem cells," writes Thomas Skutella, who leads an experimental embryology group at Tuebingen University, in the online edition of Nature.

Stem cells are the new hope for treatment development because they carry the potential of personalized therapy -- using a person's own cells to create stem cells that can then repair and replace damaged tissue, such as in Parkinson's disease, Alzheimer's and various forms of cancer.

This way the big problem of immune system rejection is overcome because the implants have the same DNA as the host.

The drawback, however, is that using stem cells from male testes, the treatment would only work on men.

Stem cells from embryos have the potential to become any cell in the body; after all, a whole person grows from a single fertilized egg. But getting stem cells from embryos is fraught with ethical problems since it involves the destruction of embryos. In Germany, stem cell research involving embryos is prohibited by federal law.

For years, scientists in Germany have been working to find legal alternative ways to make stem cells with the same ability to become any cell in the body as the embryonic stem cell.

Skutella and his colleagues had a hunch that there was another source of stem cells, ones that did not need to have genes inserted into their DNA to make them into cells that produce other cells, because they do that already: the sperm producing cells inside adult male testicles.

For their study, the German researchers used testicular tissue from 22 male volunteers between 17 and 81 years of age.

After collecting the tissues, they were isolated and then cultured to grow into stem cells.

"We made them into skin, structures of the gut, cartilage, bone, muscle and neurons," Skutella told New Scientist."The advantage these cells have in comparison to embryonic stem cells is that there is no ethical problem with these cells and that they are natural."

If further research shows that the resulting cells are normal, it could allow men to grow their own tissue for transplant.

Cells could be taken from a Parkinson's disease patient's testicles, nurtured in a laboratory and turned into brain cells. The resulting cells could be further implanted into his brain to replace those lost to the disease.

Moreover, the same method could be used to create heart, pancreatic or liver cells.

Ernest Gill/DPA/Expatica