San Francisco ? Federal regulators on Thursday approved what would be the first transplant of fetal stem cells into human brains, a procedure that if successful could open the door to treating a host of neural disorders.

The transplant recipients will be children who suffer from a rare, fatal genetic disorder.

The Food and Drug Administration said that doctors at Stanford University Medical Center can begin the testing on six children afflicted with Batten disease, a degenerative malady that renders its young victims blind, speechless and paralyzed before it kills them.

An internal Stanford review board must still approve the test, a process that could take weeks.

The stem cells to be transplanted in the brain aren’t human embryonic stem cells, which are derived from days-old embryos. Instead, the cells are immature neural cells that are destined to turn into the mature cells that make up a fully formed brain.

Parkinson’s disease patients and stroke victims have received transplants of fully formed brain cells before, but the malleable brain cells involved here have never before been implanted.