Scientists clone embryonic stem cells from a man's skin

Two years ago, scientists conducted a tiny study of the first of embryonic stem cell treatment in humans. The results were promising, but were generally considered a first step because they used infants.

Now, in a new experiment, scientists have made another breakthrough, one that's especially promising for treating maladies that tend to affect older people such as Alzheimer's and Parkinson's disease. 

In this latest study, which was published Thursday in the journal Cell Stem Cell and co-authored by Robert Lanza chief scientific officer at Advanced Cell Technologies, scientists cloned cells from two adult men to make early-stage embryos. The scientists took the nuclear DNA extracted from the skin of a 35-year-old man and injected it into human eggs donated by four women. The women's genetic material was removed from the eggs before the man's DNA was injected. The scientists duplicated the process using the DNA taken from the skin cells of a 75-year-old man. 

In both cases, scientists were able to derive tissue from the embryos that matched the DNA from the male donors. 

Stem cell research had some challenges early on when then-President George W. Bush prohibited federal funding of such research in 2001. President Barack Obama reversed that decision in 2009. 

Still, the field suffered another setback in 2012 when Geron Corporation, a central player in stem cell research since the late 1990s, abruptly halted the world's first clinical trial using embryonic stem cells and announced that it would give up stem cells entirely as an area of research. The company cited lack of funding as the reason for its decision.