Fast-forward to the end of the 21st Century: surgeons can create
new organs to order, regrow crippled spines and hearts and
reverse the damage of Parkinson's disease or diabetes with ease.
Immune rejection and waiting lists for replacement organs are
consigned to history. Doctors have been transplanting adult
Despite their medical promise, stem cells have been dogged by
political and ethical controversy because some are derived from
discarded human embryos, and because of fears and confusion
about links with human reproductive cloning. The future of stem
cell therapies was thrown deeper into doubt in late 2005, when a
leader of the field - Woo Suk Hwang, South Korea's "stem cell
king" - was found to have forged key discoveries and flouted
ethical protocols. So has the stem cell miracle been postponed?
Full of potential Embryonic stem cells (ESCs) come from
fertilised human embryos - pinhead-sized balls of cells called
blastocysts - just a few days old. In the embryo, these cells go
on to form all the tissues