NIH Director Francis Collins has approved four more human embryonic stem cell lines as eligible for federal taxpayer funding. Embryonic stem cell research is controversial because human embryos (which many of us consider unborn children) are used. Their stem cells are harvested, causing the embryo to die, and those cells are then used for medical research.
The theory is that embryonic stem cells can be used to replicate other cells in the human body, and could lead to cures for diseases and disabilities. However, the actual results produced by embryonic stem cell research have been sketchy at best–especially compared to adult stem cell research, which does not involve killing any embryos.