Why Can’t We Experiment On Human Embryonic Stem Cells?

Human embryonic stem cell research is incredibly controversial, and the current law says we can only study them for 14 days. Why is this?
Source: DNews

Human Embryo Grown in Lab
“Scientists reported Wednesday they had grown human embryos in the lab for nearly two weeks, an unprecedented feat that promises advances in assisted reproduction, stem-cell therapies and the basic understanding of how human beings form.”
discovery.com

Advance in Human Embryo Research Rekindles Ethical Debate
“Scientists have been able to make and study human embryos in their labs for decades. But they have never been able to keep them alive outside a woman’s womb for more than about a week. That limitation meant scientists were unable to conduct a range of detailed research into early human development.”
npr.org

Parkinson’s Stem Cell ‘Breakthrough’
“Stem cells can be used to heal the damage in the brain caused by Parkinson’s disease, according to scientists in Sweden. They said their study on rats heralded a “huge breakthrough” towards developing effective treatments. There is no cure for the disease, but medication and brain stimulation can alleviate symptoms.”
bbc.com
Futuristic Technology, Human Embryonic Stem Cells, The Future of Medicine, Health, Genetics, Longevity