Some of the more amazing possibilities in medical science hinge on the use of human stem cells. Embryonic stem cells can develop into any type of cell in the human body -- bone, brain, you name it -- while adult stem cells are more limited. Both types provide us with the means to regenerate damaged tissue and even grow custom donor organs.
Our abilities to harness this technology advanced significantly in 2011 when researchers at the New York Stem Cell Foundation Laboratory reprogrammed an adult human egg cell to an embryonic state, which then created a self-reproducing line of embryonic stem cells.
The researchers used a cloning technique known as somatic cell nuclear transfer to achieve their goal, taking the nucleus and its genetic material from an adult skin cell and transferring it into the egg. The resulting stem cells weren't true clones (they contained chromosomes from both the egg and the skin cells), so the technology isn't ready for therapeutic use. However, researchers hope that these findings will pave the way to an alternative source for embryonic stem cells.