Bone marrow stem cells are routinely used in transplants to treat cancer and other diseases. But they are already partly programmed and can serve as a source of only a limited range of related cells. Stem cells taken from the early foetuses (blastocyst) are flexible. These embryonic stem cells are pluripotent, and can serve as a source of any kind of cells or tissue in the body.
But use of embryonic stem cells is controversial as US federal law strictly limits the use of taxpayer funds for working with them. So researchers are seeking other sources of stem cells and Silva's team took cells from the testes of men aged 26 to 50 years old. They said that their main aim is to re-program them thereby they can be pluripotent. Then these cell lines can effectively be used to treat a number of diseases.