STEM CELLS from aborted foetuses are to be injected directly into human brains in a procedure that could open the door to treating a host of neurological disorders such as Alzheimer's and motor neurone disease.
Scientists in the United States have been given the go-ahead to transplant stem cells into six children who suffer from Batten disease, a rare but fatal genetic disorder.
The idea is to inject the sick children with healthy, immature neural stem cells that will "engraft" in a brain and turn into cells able to produce the missing enzyme.
Such an experiment showed promise in Batten-afflicted mice, but such an ethically charged test has never been tried in humans.
"I'm sure there is no threat to anyone's identity," said Arthur Caplan, director of the University of Pennsylvania's Centre for Bioethics. "But we are starting down that road."
What's more, some of the brain cells to be implanted will be derived from aborted foetuses, which Mr Caplan said raised ethical concerns.
Even Art Caplan thinks that there may be some problems with this procedure. Ethically speaking. If this doesn't raise the yuck factor, I'm not sure anything will.