The Discovery

Scientists announced yesterday they had achieved one of the most coveted goals in biology by isolating from human embryos and fetuses a primitive kind of cell that can grow into every kind of human tissue, including muscle, bone and brain.

The long-awaited discovery of so-called human embryonic stem cells – the primordial human cells that give rise to all the specialized tissues in a developing fetus – was hailed by researchers as a landmark event with vast biomedical potential.